Converting Access Objects to Data Access Pages

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CHAPTER
25
Converting Access Objects to
Data Access Pages
In this chapter
Understanding the Limitations of the DAP Conversion Process
Saving Tables as Data Entry Pages
Saving Queries as Read-Only Pages
Saving Forms as DAP
Saving Reports as DAP
1067
1075
1082
1084
Saving the Inventory by Category Report to a Page
Troubleshooting
1091
1097
In the Real World—Enhancing Data Access Page Design
1098
1066
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Chapter 25 Converting Access Objects to Data Access Pages
Understanding the Limitations of the DAP
Conversion Process
Access 2003’s Save As Data Access Page feature is available for table, query, form, and report
objects in conventional Jet .mdb files and ADP. Be forewarned—Save As DAP has a limited
repertoire and stumbles when you try to save most Northwind.mdb or Northwind.adp sample form and report objects as pages. On the other hand, Save As DAP is the quickest and
easiest way to create simple data entry pages for tables and to display query result sets in a
browser. Saving PivotTable and PivotChart views of aggregate queries as pages is the most
expeditious method of delivering data analysis pages to intranet users.
N OTE
SharePoint Team Services 2.0 lists that you import from or link to Jet or SQL server tables
and queries are similar in function to data objects saved as DAP. Chapter 26,
“Collaborating with SharePoint Team Services 2.0,” describes how to create static and
updatable lists from Jet and SQL Server 2000 tables and queries.
Like the Save As XML feature described in Chapter 23, “Exporting and Importing Data
with XML,” Save As DAP relies on ReportML to extract the property values of Access
objects. The Save As DAP feature substitutes RPT2DAP.xsl for RPT2HTML4.xsl and
transforms the intermediate XML data in ReportML format to the combination of XML
and DHTML code used by DAP. RPT2DAP.xsl shares most of RPT2HTML4.xsl’s limitations on support for native Access controls. The most important of the excluded objects are
subform, subreport, tab, and bound and unbound object frame controls. You can use
HTML inline frames (<IFRAME> elements) and VBScript code to emulate form/subform
combinations, but transforming an existing Access form object to a main page and the subform to a page in an embedded frame usually doesn’t succeed. Few conventional bound
Access forms are suited to saving as pages directly. If you can adapt the page to a banded
design, subordinate sections with navigation controls sometimes can take the place of subforms.
25
➔
To download a Wizard that generates DAP with inline frames for subforms and subreports, see “In the
Real World—Enhancing Data Access Page Design,” p. 1098.
TIP
The “Embed an Existing Page in a Data Access Page” article at
http://msdn.microsoft.com/library/en-us/dnacc2k2/html/
odc_embedpage.asp explains how to add an inline HTML frame (<IFRAME>)
and use
a server filter to emulate a form/subform combination.
Saving reports as pages is a mixed bag. Even simple reports require design tweaks to generate attractive, usable pages. An exception is Northwind.mdb’s Invoice report; it transforms
to an almost-identical representation of the original. The only missing element is the
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DatePrinted value in the Page Header section, which involves a very simple fix. For more
complex reports that include subtotals and grand totals, plan on spending at least an hour or
two making page design changes. If your reports print calculated values other than standard
aggregates of field values, be prepared to write VBScript event-handling code to generate
the values.
N OTE
The chapter requires familiarity with basic HTML authoring techniques, but you don’t
need to be a professional Web page designer. Some of the examples include simple
VBScript procedures for page navigation and passing parameters from one page to
another. You don’t need to be an experienced VBScript programmer to follow this chapter’s examples.
Saving Tables as Data Entry Pages
Saving a table as a page is the simplest Save As DAP operation. For example, do the following to save the Suppliers table as a Suppliers.htm page:
1. In the Tables page of Northwind.mdb’s Database window, right-click the Suppliers
table and choose Save As to open the Save As dialog.
2. Change Copy of Suppliers to Suppliers, and select Data Access Page (see Figure 25.1).
Click OK to open the New Data Access Page dialog.
Figure 25.1
Name the page for
the table, and choose
Data Access Page in
the Save As dialog.
3. Accept Suppliers.htm as the file name, and click OK to create the file in the current
folder.
4. After a second or two, the Suppliers page opens in Page view with a caption, data-entry,
standard page navigation section (see Figure 25.2).
Opening HTML elements;table cell values> a page in IE 6+ or Page view generates an
ADO Recordset object of the updateable snapshot type over the entire table. Specially formatted text boxes (HTML <TEXTAREA> elements) contain cell values of the table.
Following are the default display and editing characteristics of a table saved as a page:
■
The datasheet layout determines the column widths of the page. If the table has a
lookup field, the column width of the field is expanded, but the foreign key value—not
the lookup field value—appears in the column.
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■
Clicking a field caption sorts the underlying Recordset in ascending order of the field
values. For example, clicking Company Name sorts the records in alphabetic order. To
restore the original sequence, click the Supplier ID column.
■
The default record navigation control displays 10 records at a time.
navigation progresses by 10-record groups and uses the First, Previous, Next,
and Last buttons.
■ Recordset
25
■
Record-selector buttons are bitmap images stored in the Office Web Components
(OWC) Data Source control (MSODSC). When you select a record by clicking the
record-selector button, the black arrow changes to white and the background changes
to a darker shade of gray.
■
The Tab key navigates from left to right by column and the top to bottom by row.
Fields with locked values—such as Jet AutoNumber fields—aren’t tab stops. When you
reach the last column of the last visible row, the focus changes to the navigation control
buttons. Pressing Tab when the focus is on the last navigation control moves to the first
editable column of the first row.
■
The ↓ and ↑ keys don’t navigate rows in the current columns. You can assign key names
as the value of the AccessKey property of a text box to enable navigation by Alt+Key
down—but not up—the rows of the specified column. The later “Streamlining Data
Entry” section describes how to set AccessKey values for columns.
■
The Tab key positions the insertion point after the last character of an editable cell. You
must manually select the entire field (press Shift+Home or Shift+↑) if you want the text
that you type to replace—rather than extend—the existing value.
■
Jet Hyperlink fields display the text but not the link; thus, Jet hyperlinks aren’t operable. This is the opposite of the behavior of Hyperlink fields that you add to DAP from
the Field List.
■
Field- and table-level validation rules for Jet tables and CHECK CONSTRAINTs for SQL
Server tables work as expected, and referential integrity rules are enforced. For example, attempting to delete a Supplier record that has dependent records in the Products
table displays the messages shown in Figure 25.3.
Figure 25.2
Page view of a table
saved as a page is a
reasonably close rendition of datasheet
view, considering the
limitations of HTML.
The Suppliers
datasheet uses default
formatting, which displays a plain-vanilla
page.
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Figure 25.3
1069
Warning Message from Jet and SQL Server
Users receive a warning message before
deleting a record. If
deleting the record
violates referential
integrity rules, a single message from Jet
or two messages from
SQL server explain
the reason for denying the deletion operation.
Referential Integrity
Warning from Jet Table
First Referential Integrity
Warning from SQL Server
Second Referential Integrity Warning from SQL Server
■
The Input Mask property of fields is ignored. You must write VBScript event-handling
code to implement after-entry input masks, such as the >LLLLL mask for the
CustomerID field of the Customers table. For this example, the event handler must
apply the ucase function to the entry, test for the correct number of characters, and use
the asc function to verify that only letters are present.
TIP
For a VBScript workaround for lack of Input Mask capability in pages, see the “ACC2002:
Data Access Page Ignores Underlying Table’s Input Mask” Knowledge Base article at
http://support.microsoft.com/support/kb/articles/
Q299/0/09.ASP.
Web pages aren’t as effective as Access datasheets for bulk data-entry operations because
keyboard shortcuts for editing operations—such as copying field values from the preceding
row—aren’t available in IE.
Enhancing the Page’s Appearance
A few simple design changes can dress up the table-based page and improve the usefulness
of the display. The following sections offer suggestions for making table-based pages resemble the style of pages that you create in Page Design view or that the Layout Wizard creates
for you.
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Adding Heading Elements with the Script Editor
Unlike pages that you create from scratch, pages saved from datasheets don’t have empty
<H1> and <H2> elements for adding a heading and explanatory text to the table. Adding elements to table-based pages requires adding HTML code with the Script Editor.
➔
To review use of the Microsoft Script Editor, see “The Microsoft Script Editor,” p. 1012.
To add <H1> and, optionally, <H2> elements, do the following:
1. With the Suppliers page open, change to Page Design view and click the Microsoft
Script Editor button to open the source window for your page.
2. By default, the Script Editor adds HTML tag names in lower case, which conforms to
XHTML standards; RPT2DAP.xsl generates upper-case tag names. To change the tag
name case, choose Tools, Options, to open the Options dialog. Expand the Text Editor
and HTML nodes, and select Format.
3. Select Uppercase in the Generated HTML list. If you want to make your changes more
evident, mark the Tag Start: Before and Tag End: After check boxes (see Figure 25.4).
Click OK to close the Options dialog.
Figure 25.4
25
The Script Editor
defaults to lowercase
tags. You change to
uppercase tags in the
Option Dialog’s HTML
Format page. You also
can specify line
breaks in the code
before and after tag
pairs.
TIP
You can reduce toolbar clutter by choosing View, Toolbars, and toggling the Design,
Formatting, and Text Editor toolbars off. Only the Standard toolbar is useful for the HTML
editing examples in this chapter.
4. After the <TITLE> tag, change Suppliers to Suppliers Table Data Entry.
5. Press Ctrl+F to open the Find dialog, type body, and press Alt+F twice to locate the
<BODY>
tag that follows the </HEAD> tag.
6. Move to the end of the line, and press Enter to create a new line.
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7. Type <h2, which opens the HTML statement-completion window and selects the H2
item. Double-click H2 and type > to create an <H2></H2> tag pair. Type the title that
you added in step 4 between the tag pair as the heading for the form. As you add the
HTML content, Page Design view displays the changes.
8. Optionally, add a <P></P> tag element;adding to table-based pages> element;adding to
table-based pages> pair with explanatory text after the heading. To center the lines, type
a <CENTER> tag before the <H2> element, and type </CENTER> after the </P> element. Remove the extra </CENTER> and <CENTER> tags that the statement completion
feature adds (see Figure 25.5), and close the Script Editor.
Figure 25.5
The HTML code
between the
<CENTER> and
</CENTER> tags adds
an 18-point heading
and a text paragraph
to the page.
25
TIP
Close the Script Editor before making further changes in Page Design view. If you leave
the Script Editor open it’s difficult—and sometimes impossible—to alter control positions
or sizes.
9. Return to Access, select all captions, and click the Bold button. Press Ctrl+S to save
your changes.
10. Change element;adding to table-based pages> element;adding to table-based pages> to
Page view to check your work so far (see Figure 25.6).
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Chapter 25 Converting Access Objects to Data Access Pages
Figure 25.6
The added HTML
code of Figure 25.5
provides the heading
and text shown here.
After you add the elements, you can edit
their text in Page
Design view.
N OTE
If you’ve specified a default theme, the styles of the theme determine the color, font, and
size attributes of the elements that you add. Otherwise, the attributes default to the standard style for DAP.
Modifying Fixed Page Layout and Design Elements
25
A few additional design changes make the page more attractive and make the appearance
conform to the DAP that you created from scratch in Chapter 25, “Designing and
Deploying Data Access Pages.” The sections of DAP that you save from Access objects have
fixed positions and dimensions, so you must change section property values to alter the
overall design of the page.
To make the form-based design of saved datasheets resemble the standard format of the
other pages you’ve created, using the Suppliers.htm page as an example, do the following:
1. Return to Page Design view, and double-click the Caption: Suppliers section heading to
open its properties window.
2. Change the BackgroundColor property value to steelblue and the Height to 25px.
3. Select all the captions, open the Fore/Font Color picker, and click the white square.
4. With all captions selected, drag the captions down one grid dot.
5. Change the Supplier ID caption to ID and decrease its width to fit the text.
6. Decrease the width of the Supplier ID text box to match the width of the ID caption,
and select and drag the remaining text boxes to the left. Dragging the text boxes also
drags the labels.
7. The Home Page hyperlink field isn’t functional in the Suppliers page, because the page
link isn’t present. Delete the field and its caption.
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8. The width of the active area of the page is set by the fixed Width property of the record
navigation section. Double-click the NavigationSuppliers section, and set the Width
property value to 13.75in.
9. To add a small margin around the page elements, open the Script Editor and change
the <BODY
style=”MARGIN: 0px
attribute to 17px.
10. Press Ctrl+S to save the edits, close the Script Editor, and change to Page view to
review your work (see Figure 25.7).
Figure 25.7
Adding a background
color to the caption,
reducing the width of
the Supplier ID column, and adding a
margin improves the
appearance of the
page.
25
Streamlining Data Entry
The width of the sections exceeds the visible page widths on ordinary monitors, so editing
values in more than one row of columns that aren’t visible is a painfully slow process.
Tabbing through columns and then rows causes the display to flash, which leads to dataentry operator fatigue. To navigate by rows of a particular column, you add AccessKey property values to each updateable field.
Access key column navigation is limited to the number of rows displayed by the Header
section. The 10-row default creates a page that resembles a form more than a Web page.
Forms usually have about a 4:3 width-to-height aspect ratio to avoid scrolling the form, but
users are accustomed to scrolling Web pages vertically. Displaying more rows of the table in
a group aids navigation, especially when combined with column access keys.
To add and test AccessKey values for the columns of the sample Suppliers.htm page and
increase the number of rows on the page, do this:
1. In Page Design view, double-click the Company Name text box to open the Text Box:
CompanyName window.
2. Click the Other tab and type 1 as the AccessKey value. Alternatively, type a letter that’s
easier to reach with a thumb or finger on the Alt key.
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Chapter 25 Converting Access Objects to Data Access Pages
3. Select each text box in sequence, and specify a different AccessKey value. This example
uses 1, 2, 3, … 0 for the 10 active fields of the Suppliers table. (SupplierID is an
AutoNumber or identity field, so it isn’t active.)
4. Right-click the page and choose Group Level Properties to open the Group Level:
Suppliers window, and set the DataPageSize property value to a larger number. Select
All if you want to scroll the entire Recordset.
5. Press Ctrl+S to save your changes, and then open the page in Web Page Preview. Click
the Company Name header to sort the page by company.
6. Press Alt+5 (or the letter that you chose) to move the insertion point to the end of the
City name in the first row (see Figure 25.8). Pressing the same key combination repeatedly scrolls the City column. When you reach the last row of a list that’s less deep than
IE’s window, the insertion point returns to the first row of the City column. Otherwise
the insertion point returns to the first row of the page.
Figure 25.8
25
You can sort the page
by clicking a column
heading or selecting a
column and clicking
the A-Z or Z-A buttons. This view is
sorted by city.
Pressing
Alt+AccessKey navigates horizontally to
the designated column and then vertically through the
rows.
Unfortunately, you can’t freeze fields to make the Supplier ID and Company Name field
visible while you edit other fields.
It’s a good practice to delete buttons in the PageNameNavigation section that aren’t necessary for data entry. For example, the Help button opens the “About Data Access Pages”
help topic; installing the Office Web Components (OWC) 11 runtime on client PCs adds
this help file. The help file contains more information than most data-entry operators need.
Depending on your application, you might want to remove the filter buttons. To remove a
button, in Page Design view, select the button and press Delete. Removing unneeded buttons also improves page performance.
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➔
1075
To make the data entry page available to users, see “Delivering Pages on an Intranet or the Internet,”
p. 1057.
If you encounter problems opening the page from a networked computer other than the one on
which you’re designing the page, see the “Data Source Problems” topic of the “Troubleshooting”
section near the end of the chapter.
Saving Queries as Read-Only Pages
Saving query datasheets as DAP is an alternative to creating the live Web reports described
in Chapter 23. If the query is updateable, you can edit the result set by the methods
described in the preceding section. In most cases, however, pages based on queries are readonly, even if the result set is updateable.
Datasheets with special formatting preserve the format by changing the Cascading Style
Sheet (CSS) style for text boxes. For an example, save the Customers and Suppliers by City
UNION query to a page that closely resembles the query’s Datasheet view. To make the entire
text box visible, you must increase the depth of the Header section from 17 to about 21 pixels and then expand the depth of text boxes, which appear as command buttons in Page
Design view. On the whole, special effects applied to datasheets are less than special in
pages.
Designing the Query Layout for DAP
If you intend to save a query as a page, it’s faster to change the column captions, when possible, and the column widths in Datasheet view. Changing the default Medium Date to Short
Date format makes date columns consistent with other pages that use MM/DD/YYYY format. Figure 25.9 shows a sample Jet qryOrdersPage query in Datasheet view; column widths
are minimized to ensure full display within IE 6+ maximized 800×600 monitor resolution.
Applying a descending sort on the OrderID column displays latest orders first.
Figure 25.9
Adjusting column
widths, captions, and
formatting of queries
before you save the
page minimizes
redesign effort. For
orders, it’s usually
preferable to set the
default sort order to
descending.
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When you save the query as a page, RPT2DAP.xsl might transform the design incorrectly.
In this case, the Order ID caption doesn’t fit the allotted space, so the caption and all rows
have a two-line depth (see Figure 25.10).
Figure 25.10
RPT2DAP.xsl interprets the insufficient
width for the Order
ID caption as requiring an increase in the
depth of the rows.
25
The solution to this problem is to change Order ID to ID in the caption, and delete the
Order ID text in the first text box of the header. (Field names aren’t necessary in Page
Design view of text boxes.) You don’t need record-selector buttons for a read-only query, so
right-click the page, choose Group Level Properties, and set the RecordSelector property
value to False. After making design changes similar to those recommended in the preceding
two sections, your page appears as shown in Figure 25.11. The New, Save, Undo, and Help
buttons are deleted because the query result set is read-only.
Figure 25.11
Design changes for
table-based pages
described earlier have
been applied to the
query-based page
shown here. When
you remove the
record-selector buttons, the left border
of the text box for the
first column is
missing.
TIP
As an alternative to setting all margins at once by changing the <BODY style=
attribute value, you can change individual margins on the Format page
of the Page: PageName window. Set the MarginLeft and MarginTop property values
to 17px (or more).
”MARGIN: 0px
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To add a left border to the text boxes in the Header section, double-click the text box with
the missing border—in this case, ID—to open its properties window. Delete the last #000000
value of the BorderColor property and delete the last none value of BorderStyle.
TIP
To minimize active connections to the database, open the Page: PageName properties
sheet, click the Data tab, and use the RecordsetType property’s list box to change the
default dscUpdateableSnapshot to dscSnapshot.
The qryOrdersPage query and a Current Orders link to the CurrentOrders.htm page are in
the Data25.mdb file located in the \Seua11\Chaptr25 folder of the accompanying
CD-ROM.
Working with Parameterized Queries
Users opening pages based on queries download the entire query result set to a local
Recordset, unless you add a TOP n modifier or a WHERE clause to limit the number of rows.
Alternatively, you can add a parameter to the query to limit the Recordset size. For this
example, the parameter is the earliest order date to view. To avoid errors that result from
not typing the parameter value in the exact date format, add a hidden OrderDate column
and type >=[Enter Earliest Order Date (M/D/YYYY)] or the like in the Criteria row of
the query. (Keep your parameter captions short for pages.)
Jet SQL
The Jet SQL statement for the qryOrdersPageParam parameter query used in the following sections is:
PARAMETERS [Enter Earliest Order Date (M/D/YYYY)] DateTime;
SELECT Orders.OrderID, Customers.CompanyName,
Format([OrderDate],”mm/dd/yyyy”) AS [Order],
Format([ShippedDate],”mm/dd/yyyy”) AS Ship,
[Order Subtotals].Subtotal AS Amount,
Orders.Freight, Shippers.CompanyName
FROM Shippers
INNER JOIN (Customers
INNER JOIN (Orders
INNER JOIN [Order Subtotals]
ON Orders.OrderID = [Order Subtotals].OrderID)
ON Customers.CustomerID = Orders.CustomerID)
ON Shippers.ShipperID = Orders.ShipVia
WHERE (((Orders.OrderDate)>=[Enter Earliest Order Date]))
ORDER BY Orders.OrderID DESC;
Supplying Parameter Values in the Enter Parameters Dialog
When you open the page in Page View or Web Page Preview, a nonstandard Enter
Parameters dialog appears first. The dialog can accommodate about 12 parameter values,
but the Name list doesn’t expand to accommodate fully descriptive parameter captions.
Figure 25.12 shows the Enter Parameters dialog for the CurrentOrdersParam.htm page.
25
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Chapter 25 Converting Access Objects to Data Access Pages
Figure 25.12
A single parameters
dialog replaces one or
more Access Enter
Parameter Value
dialogs. The first
Microsoft mystery of
this chapter is why
the parameter names
are centered instead
of left-justified in the
list.
Typing the required value and clicking OK (or pressing Enter twice) sends the parameter
value(s) to Jet and opens the page. If you don’t enter a value and click OK, no rows appear.
If you click Cancel, the page opens with #Name? values in a single row. The parameter
entry procedure is the same for SQL Server parameterized stored procedures and tablereturning functions.
TIP
25
If you copy the parameterized query with a different name—such as qryOrdersParam—
and use Save As to save the link and page with a different link and .htm file name, you
must change the RecordSource property value on the Data page of the Section:
NavigationQueryName window to point to the parameterized query. Open the
RecordSource list, and scroll to the Procedure: items—not Query: items—to find the
new parametized query (see Figure 25.13). The Procedure: prefix applies to Jet parameterized queries and SQL Server stored procedures with parameters.
Figure 25.13
When you change the
RecordSource property from a conventional query to a
parameterized query,
select the query name
from the items with
the Procedure: prefix.
The qryOrdersPageParam query and a Current Orders (Param) link to the
CurrentOrdersParam.htm page are in the Data25.mdb file located in the
\Seua11\Chaptr25 folder of the accompanying CD-ROM.
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Passing Filter Criteria from One Page to Another with Cookies
The Enter Parameters dialog isn’t user-friendly, and it limits the explanation of the required
parameter entry to a few words. A better alternative is an initial page in which users type
one or more parameter values in text box(es), and then click a button or a label formatted as
a hyperlink to open a second page that displays the data. The onClick event handler of the
button or label writes a cookie with the parameter names and values, and then opens the
other page. The second page retrieves the cookie and passes the values as query parameter
values or the criterion value for the DataSourceControl’s ServerFilter property. One of the
advantages of using an initial page is that you can provide a default value for the parameter
in a text box.
N OTE
The DataSourceControl’s ServerFilter property is similar to the Filter property of
a table or query. The Filter property downloads the entire Recordset and then applies
the filter on the client. Applying a ServerFilter downloads only those records that
meet the filter criterion, which minimizes network traffic and speeds response time.
Cookies are a means for passing variable values between conventional HTML forms.
Cookies are Name=Value pairs—called crumbs—separated by semicolons. Cookies can contain up to 20 crumbs. Unless you add an expires=datetime crumb, a cookie ordinarily stays
in memory only while the browser is open. In Access, the cookie stays in memory while the
page is open in Page or Page Design view. Cookies are properties of the browser’s document
object; you create a cookie with a VBScript document.cookie = “Name=Value” statement
and retrieve it with a strVariable = document.cookie statement. Obtaining the value of a
crumb requires parsing the cookie with VBScript string-manipulation functions. VBScript
doesn’t support all Jet/VBA string-manipulation functions; those that VBScript does support—with a few exceptions—use the same syntax as their Jet/VBA counterpart.
N OTE
Like VBA, VBScript isn’t case sensitive. Web programmers use a variety of capitalization
styles when writing VBScript code. A common style is to use lower case for VBScript key
words and object, property, and method names defined by the Document Object Model.
Mixed case is used for variable names and other object names—such as
MSODSC.RecordsetDefs for the RecordsetDefs collection of the Microsoft Office
Data Source Control. This book uses mixed case for VBScript.
VBScript has only one data type—Variant. The VBScript examples of this chapter use
variable-type prefixes—such as dat for date and str for character variables—for consistency with the VBA code that you encounter in Part VII, “Programming and Converting
Access Applications.”
You can create the initial page in the Access page designer or any other HTML editor, such
as FrontPage 2003. The initial page might include navigation buttons or labels for several
related pages. Figure 25.14 shows a simple navigation form with links to the
CurrentOrders.htm and CurrentOrdersCookie.htm pages.
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Chapter 25 Converting Access Objects to Data Access Pages
Figure 25.14
OrderStatusPages.htm
is an unbound navigation page that has a
link to
CurrentOrders.htm
and a text box for
entering the earliest
order parameter
required when clicking the link to the
CurrentOrdersCookie.
htm page.
TIP
When you deploy a navigation page with links to other pages, create a virtual directory
for it and all related pages in Internet Information Server (IIS). Rename the navigation
page to Default.htm. Users enter http://servername/directoryname/ to open
Default.htm; filename.htm isn’t required.
25
The hyperlinks of the navigation page of Figure 25.14 are formatted labels (blue color,
underlined). The Show All Orders in a Form link’s onClick event handler contains the following VBScript code to open the CurrentOrders.htm page:
<SCRIPT language=vbscript event=onclick for=lnkAllOrders>
<!-dim strURL
strURL = “CurrentOrders.htm”
window.navigate(strURL)
-->
</SCRIPT>
N OTE
The preceding event-handler code is typical for links or buttons on pages that perform
navigation functions similar to that of Northwind.mdb’s Main Switchboard form.
The Show Orders Up To and Including… link (lnkLatestOrders) points to
CurrentOrdersCookie.htm and has a text box (txtEndDate) that contains a default value
appropriate for the range of the latest orders in the Northwind.mdb Orders table. The following code illustrates how to create the parameter cookie (LastOrder=11000) before opening the CurrentOrdersCookie.htm page.
<SCRIPT language=vbscript event=onclick for=lnkLatestOrders>
<!-Dim strURL
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Dim lngLastORder
Const strParam1 = “LastOrder”
strURL = “CurrentOrdersCookie.htm”
lngLastOrder = txtLastOrder.value
document.cookie = strParam1 & “=” & lngLastOrder
window.navigate(strURL)
-->
</SCRIPT>
The following VBScript added to the CurrentOrdersCookie.htm page reads the cookie,
extracts the date from the cookie text, and adds a ParameterValues object to the
MSODSC.RecordsetDefs collection.
<SCRIPT language=vbscript event=BeforeInitialBind(varParams) for=MSODSC>
<!-Dim lngLastOrder
Dim strCookie
strCookie = document.cookie
If Len(strCookie) > 0 Then
‘Extract the date from the cookie
lngLastOrder = Mid(strCookie, InStr(strCookie, “LastOrder=”) +10)
If InStr(lngLastOrder, “;”) Then
‘Remove trailing cookie name-value pairs
lngLastOrder = Left(lngLastOrder, InStr(lngLastOrder, “;”) - 1)
End If
MSODSC.RecordsetDefs(“qryOrdersPage”).ServerFilter = “OrderID >= “ &
lngLastOrder
Else
MSODSC.RecordsetDefs(“qryOrdersPage”).ServerFilter = “OrderID >= 11050”
End If
-->
</SCRIPT>
➔
To review the syntax of the Mid and InStr functions, which is the same in VBA and VBScript, see
“Text-Manipulation Functions,” p. 373.
For an alternative and more complex VBScript example for passing query parameters
between pages, search for “Passing Parameters to a Data Access Page” (include the quotes)
at http://msdn.microsoft.com.
The OrderStatusPages.htm, CurrentOrders.htm, and CurrentOrdersCookie.htm files are in
the \Seua11\Chaptr25 folder of the accompanying CD-ROM. To test passing a parameter
with a cookie, open OrderStatusPages.htm in IE and then click the Display Latest Orders…
link.
TIP
Don’t attempt to pass a cookie value to another page in Page view; both pages must run
in IE to share the cookie. The preceding code substitutes a constant OrderID value
(11050) to prevent an error or downloading the entire Recordset.
25
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If your navigation page’s link opens an empty page whose data source is a parameterized query,
see the “Parameter Naming and Cookie Parsing Problems” topic of the “Troubleshooting” section
near the end of the chapter.
Saving Forms as DAP
The ReportML transform isn’t named FormML for a good reason—saving forms as DAP
has severe form design limitations. Most forms have subforms, tab controls, or other objects
that ReportML ignores. For example, saving Northwind.mdb’s sample Employees form as a
page results in colorful—but empty—Caption: Employees and Header: Employees sections.
Saving the Customer Phone List form creates a page with elements for the form header,
detail, and footer section. The Caption section has an extra line of field-name captions, and
the 26 command buttons to filter the records are missing from the option group below the
navigation control (see Figure 25.15). Loss of the command buttons isn’t a major issue
because the form relies on Access macros to filter the detail records.
Figure 25.15
25
Saving to DAP forms
that generate simple
lists usually works,
but you must tweak
the page design in
most cases.
Saving a form (or a report) that has a Class Module saves the VBA code as a comment block
between BEGIN VBA CODE and END VBA CODE comments (see Figure 25.16). The purpose of
saving the code in the script is to aid you when rewriting the code in VBScript, if possible.
N OTE
Access 2003 doesn’t let you save unbound forms as DAP. Access 2002 could save
unbound forms, such as Main Switchboard, to non-functional replicas.
Following are a few types of forms that you can save as DAP with varying degrees of
success:
1. Simple forms without subforms, such as the Customer Phone List. Bound combo boxes
used for lookup and other operations are empty. Bound subforms display all records
from the underlying table or query.
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Figure 25.16
The Script Editor displays the VBA code
that you can use as a
reference when
attempting to emulate
the form’s actions
with VBScript.
2. Subforms that contain bound PivotTable or PivotChart objects. For example, the
sbf1997SalesPivotChart subform that you created in Chapter 18, “Adding Graphs,
PivotCharts, and PivotTables,” retains all its properties when saved as a page. You must
specify the Default View property as PivotTable or PivotChart to create the correct version of the page. Replace the missing caption supplied by the parent form with a title
(see Figure 25.17).
Figure 25.17
PivotChart views of
forms or subforms
save correctly as
pages. A page saved
from Chapter 18’s
sbf1997SalesPCLinked
graph displays eight
lines instead of the
single line specified
by the link to the
frm1997SalesPCLinked
form.
25
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3. Bound pop-up forms and dialogs that don’t contain unsupported controls. Pop-up
forms and dialogs are better displayed as Web Page Dialogs—such as the
Employees.htm page opened by the Review Orders.htm page.
Saving Reports as DAP
RPT2DAP.xsl does a better job saving simple reports than saving forms as pages. Grouping
levels in reports transform to GroupLevelx page sections with a navigation control; detail
sections also gain a navigation control. Grouped sections are collapsed by default.
Following is a list of the most commonly used features of reports that don’t survive the Save
As process:
25
■
Subreports—like subforms—are ignored. You must modify the resulting page—such as
by adding an embedded inline frame containing a page—to emulate subreports.
■
VBA code in the report’s Class Module appears in the script as a comment block.
■
You can’t group by expressions that aren’t supported by the Group On property of the
report’s group. The Alphabetic List of Products report handles the report’s
=Left([ProductName],1) grouping expression correctly because the report’s Group On
property value is set to Prefix Characters in the Sorting and Grouping dialog.
■
Aggregate values in the outermost grouping section move below the navigation control
in the navigation section. Text boxes lose their ControlSource property value when
moved to this section.
■
Aggregate value expressions in section footers don’t work. You receive an error message
if your report includes text boxes to display the result of aggregate expressions, such as
=Sum([FieldName]).
■
Expressions in the report’s group headers and footers aren’t supported.
■
You can’t add bound controls to a caption.
■
The Can Grow and Can Shrink properties are ignored.
The restriction on subreports and loss of VBA code in Class Modules makes it difficult or
impossible to save complex reports as useful DAP. Only 3 of the 11 sample Northwind
reports—Alphabetical List of Products, Invoice, and Products By Category—save as readable pages.
Modifying the Alphabetical List of Products Page
The Alphabetical List of Products report is simple enough for RPT2DAP.xsl to convert
without modifying the report before the transformation. The resulting page, however,
requires many modifications to improve its appearance and usefulness. The design changes
that you make to this report are typical for many simple reports saved as DAP.
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To save the Alphabetical List of Products to a page, do the following:
1. In the Database window’s Reports page, right-click Alphabetical List of Products and
choose Save As to open the Save As dialog.
2. Delete Copy Of in the text box, select Data Access Page in the As list, and click OK to
open the New Data Access Page dialog.
3. Shorten the file name of the page to ProductList.htm, click Yes to enable scripts, and
click OK to open Page view of the transformed report. Expand one or more of the sections to verify the presence of detail records (see Figure 25.18).
Figure 25.18
The Alphabetical List
of Products report
creates a page with a
navigation control for
each group. It’s obvious that this page
needs a makeover for
viewing in a browser.
25
\
4. Change to Page Design view, and start redesign by dragging the empty text box below
the title to the right of the title. Drag the caption labels from the Header:
GroupLevel0 to the Caption: GroupLevel0 section to prevent repetition in every group
level, and delete the colon suffix. Drag the line to under the captions, and drag the bottom of the Caption section to just below the line. Look ahead to Figure 25.19 for control positioning.
TIP
As you make changes to the page, switch to Web Page Preview to check your work.
Opening the page in IE 6+ doesn’t clear the undo stack when you save changes.
5. Navigation controls aren’t appropriate unless the page has many rows in each section,
which isn’t the case with this page. Right-click in the Header: GroupLevel0 section,
and clear the Record Navigation check box. Do the same for the Header: Alphabetical
List of Products section.
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TIP
Use Ctrl+ArrowKey or Ctrl+Shift+ArrowKey to make fine adjustments to the position of
the controls.
6. In the Header: GroupLevel0 section, move the text box to the right of the Expand control. Double-click the Expand control, click the Other tab, and change the Src property
value to Black Arrow. Drag the bottom of the section to the bottom of the text box.
7. Drag the bottom of the Header: Alphabetical List of Products to the bottom of the text
boxes.
8. In the Footer: GroupLevel0 section, move the line up a few pixels, delete the empty
text box in the footer, and drag the bottom of the section up.
9. Optionally, change the font of the labels and text boxes to match the font used in other
DAP—Tahoma, for the examples in this book. The design at this point appears as
shown in Figure 25.19.
Figure 25.19
25
The page design
changes shown here
make the transformed
report appear more
like a conventional
page.
10. To add a date to the empty text box in the Caption section, double-click the text box,
click the Data tab of its properties window, and type =Date() in the DefaultValue text
box. Right-align the text, add the bold, and remove the italic attribute.
N OTE
Setting the Format property value has no effect on the date display in Page view.
11. The width of the QuantityPerUnit field is larger than required, so you can add the
Unit Price field to the left of the Units in Stock field. Decrease the width of the text
box to two grid dots wider than the Quantity per Unit label. Open the Field List and
the Toolbox, select the Bound Span control, and drag the UnitPrice field to the right of
the shortened text box. Move the Price label to above the new field.
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TIP
Use bound span controls instead of text boxes wherever possible to improve page performance. If you add a text box, you must change the format of the text box to prevent
its borders from appearing on the page.
12. Change to Web Page Preview to display the redesigned report in IE (see Figure 25.20).
Figure 25.20
Page view of the
redesigned page
resembles the sample
Review Products page
but doesn’t repeat
captions.
25
The Alphabetical List of Products link to the ProductList.htm page is in the Data25.mdb
file located in the \Seua11\Chaptr25 folder of the accompanying CD-ROM.
Using a ServerFilter to Display a Single Invoice Page
The Invoice report is an example of a report that you can save to a page without a major
design change. An Invoice page also is a candidate for addition to the
OrderStatusPages.htm page with the order number—the same as the invoice number—
passed by a cookie.
Creating and Modifying the Invoice Page Design
To transform the Invoice report to an Invoice.htm page and modify its design, do this:
1. Right-click the Invoice report item in the Database window, choose Save As, and
change the name to Invoice. Then select Save As Data Access Page, click OK, and
click Yes to dismiss the warning message, if it appears, to save the page as Invoice.htm.
3. Click the Expand control above the Ship To label to display the Order Details items.
Verify that the Subtotal and Total amounts calculate correctly.
4. Change to Page Design view, and double-click the DatePrinted text box. Click the
Data tab of the properties window, and type =Date() as the temporary DefaultValue
property value.
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5. You don’t need navigation controls for this page, so right-click Header: GroupLevel0
and clear the Record Navigation check box. Do the same for the Header: Invoices
Filter.
6. Right-click Header: GroupLevel0 again and select Group Level Properties. Doubleclick the ExpandByDefault property to change its value from False to True. Delete the
Expand control under the Header: GroupLevel0. Save your changes.
7. Open the page in Web Page Preview to verify the design changes in IE (see Figure
25.21) and then close IE.
Figure 25.21
The modified Invoice
page has the Expand
and record navigation
controls removed and
the missing Date
value added.
25
Adding the VBScript Code to Accept the Invoice Number Cookie
If you created the OrderStatusPages.htm navigation page in the earlier “Passing Filter
Criteria from One Page to Another with Cookies” section, you can add a line to the page to
navigate to a specific invoice. This section demonstrates how to reuse VBScript code that
you added to the CurrentOrdersCookie.htm page in the Invoices.htm page.
To add the VBScript required to accept a cookie value from the OrderStatusPages.htm
page, do the following:
1. In the Database window, select the Invoice page and save it as Invoice (Cookie) with
InvoiceCookie.htm as the page file name.
2. Select the Current Orders (Cookie) item and click the Microsoft Script Editor button
to open the Script Editor for the CurrentOrdersCookie.htm page.
3. Scroll to and select the <SCRIPT>...</SCRIPT> block for the BeforeInitialBind event,
copy it to the Clipboard, close the Script Editor, and close the page.
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4. In Page Design view of the InvoiceCookie.htm page, click the Microsoft Script Editor
button, go to the same location in page (after the <![endif]--> tag, press Enter, and
paste the script block.
5. Change all instances of lngLastOrder to lngInvoiceNum, +
10
to +11, two instances of
qryOrdersPage to Invoices and, >= to = (see Figure 25.22).
Figure 25.22
Reusing VBScript code
from another page
saves time. Only
minor modifications
are required to
CurrentOrdersCookie.
htm code to display a
single invoice.
25
6. Save your script changes.
You can verify that the ServerFilter works by opening InvoiceCookie.htm in IE and verifying display of the default order 11077.
Changing the DatePrinted Value to the Shipping Date
The Invoice report displays the system date in the DatePrinted span. Ordinarily, the invoice
date is the date shipped, although some firms have been known to issue invoices for products not shipped or services not rendered. To comply with generally accepted accounting
practices (GAAP), the invoice date should be blank if the goods haven’t been shipped.
Failure to use the shipping date as the invoice date is another Microsoft mystery.
The solution to this problem is to set the innerText property of the page’s DatePrinted
span to the innerText property of the ShippedDate text box. The VBScript code to make
the change is simple and illustrates how to write event handlers for the Date Source
Control. MSODSC has many more events than the ActiveX Data Object (ADO) Recordset;
most of the events have equivalents in bound Access forms.
To make the change to the ShippedDate span, do this:
1. With Script Editor open with the Invoice.htm page, navigate to a position above or
below the cookie script that you added in the preceding section. Add an empty line
between the </SCRIPT> and </BODY> tags.
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2. With the insertion point on the empty line, choose MSODC in the Object (Client
Object & Events) list, open the Event list, and select DataPageComplete to add an
event-handling stub.
3.
events require a parameter placeholder, even if the event doesn’t return a value
to the parameter. Add (varParam) to the event=DataPageComplete argument to make
the event handler work.
MSODSC
4. Add a DatePrinted.value
= ShippedDate.value
statement. The complete event handler
code is
<SCRIPT language=vbscript event=DataPageComplete(varParam) for=MSODSC>
<!-DatePrinted.value = ShippedDate.value
-->
</SCRIPT>
5. Save your changes, close the Script Editor, and close the page.
You can’t test your addition to the script until you complete the next section.
Adding a Link to Open the Invoice Page
25
Adding a link for the Invoice.htm page to the OrderStatusPages.htm page is similar to
adding the link to the CurrentOrdersCookie.htm page in the earlier “Passing Filter Criteria
from One Page to Another with Cookies” section. You copy the existing link, text box, and
label, change their Id values, and add a modified copy of the VBScript code for the new
link’s onClick event.
To add the link to the Invoice.htm page, do this:
1. Open Order Status Pages in Page Design view, and select the link, text box, and label.
Press Ctrl+C and Ctrl+V to create a copy.
2. Change the text of the link and label, and reduce the width of the text box. Type a
default order number in the text box (see Figure 25.23).
Figure 25.23
Add links to other
pages in the Order
Status Pages page by
copying and editing
preceding links.
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3. Double-click the link, click the Other tab of the properties window, and change the Id
property value to lnkInvoice. Select the text box and change its Id to txtInvoice, and
change the Id of the label to lblExplainInvoice, as shown in Figure 25.23.
4. Open the Script Editor, and copy and paste the VBScript block for lnkLatestOrders.
Edit the event handler code as follows:
<SCRIPT language=vbscript event=onclick for=lnkInvoice>
<!-dim strURL
dim lngInvoice
const strParam1 = “InvoiceNum”
strURL = “InvoiceCookie.htm”
lngInvoice = txtInvoice.value
document.cookie = strParam1 & “=” & lngInvoice
window.navigate(strURL)
-->
</SCRIPT>
5. Save your changes, close the Script Editor, and open the page in Web Page Preview.
Click the three links to test the code that you added in this section and the preceding
section.
The Invoice link to the InvoiceCookie.htm page is in the Data25.mdb file located in the
\Seua11\Chaptr25 folder of the accompanying CD-ROM.
Saving the Inventory by Category Report to a
Page
The Inventory by Category report (rptInventoryByCategory) that you created in
Chapter 16, “Working with Simple Reports and Mailing Labels,” is a candidate for conversion to a page. This report illustrates problems that you encounter with aggregate values in
group footer sections—the mysterious error message shown in Figure 25.24 appears during
the transformation process. It’s a common practice to use text boxes with aggregate functions in report group footers, so you’re likely to see this message often. Loosely translated,
the error message means that RPT2DAP.xsl doesn’t translate =Sum([FieldName]) expressions
into the required GroupOfFieldName function for section aggregates.
When you click OK to acknowledge the message, the page opens with #Name? as values of
aggregate text boxes. Clicking the Expand button to display rows of the detail section opens
an “Operation is not allowed when the object is closed” message (see Figure 25.25). The
Category name is missing because pages don’t display lookup field values. You can’t put
aggregates in the outermost footer, so there’s no Grand Total value. To create a page that
you can modify to comply with page design rules, you must delete the text box expressions
and then save the modified report as a page.
25
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Figure 25.24
This error message
appears when the
report that you save
as a page has an
aggregate expression
in a group footer.
Figure 25.25
After acknowledging
the error shown in
Figure 25.24, the page
opens with errors and
missing elements.
Another error message appears when
you click the Expand
control.
25
Modifying the Source Query to Supply Required Field Values
For this example, substituting CategoryName and supplier CompanyName values for
lookup fields requires redesigning the source query—qryInventory, for this example. You
must also supply fields to replace the calculated Cost and Value columns because the page
section Value aggregates depend on field values. The once-simple qryInventory query
requires a total makeover. Fortunately, the required changes to the query don’t affect the
design of the original rptInventoryByCategory report.
Jet SQL
The SQL statement for the modified qryInventory query is:
SELECT Products.ProductID, Products.ProductName, Products.QuantityPerUnit,
Products.UnitPrice, CCur(0.667*[UnitPrice]) AS Cost, Products.UnitsInStock,
CCur([UnitsInStock]*[Cost]) AS [Value], Categories.CategoryID,
Categories.CategoryName, Suppliers.SupplierID, Suppliers.CompanyName
FROM Suppliers INNER JOIN (Categories
INNER JOIN Products
ON Categories.CategoryID = Products.CategoryID)
ON Suppliers.SupplierID = Products.SupplierID
WHERE (((Products.Discontinued)=False));
The modified qryInventory query is in the \Seua11\Chaptr25\Data25.mdb file.
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Creating and Modifying the Source Report for the Page
To permit saving the sample report as a page and to simplify the page redesign process, do
the following:
1. Save a copy of rptInventoryByCategory as rptInventory.
2. Open rptInventory in Report Design view. In the Detail Section, right-click the
SupplierID drop-down list and choose Change To, Text Box. Replace SupplierID with
CompanyName as the Control Source value.
3. Delete the expression in the Cost field, and type Cost as the field name. Do the same
for the Value text box, but type Value.
4. In the CategoryID footer section, change the CategoryID list to a text box, and delete
the CategoryID field name. Delete the expressions in the remaining four text boxes in
the CategoryID footer. All text boxes display Unbound as their value.
5. Delete the two text boxes in the Page Footer section, and move the Report Footer section up. Your redesigned source report appears as shown in Figure 25.26.
Figure 25.26
The changes shown
here are required to
eliminate errors when
transforming the
report to a page and
to specify the
columns to display
from the modified
source query.
6. Change to Print Preview to check your work. Close rptInventory and save your
changes.
7. Right-click rptInventory in the Database window, choose Save As, and save the report
as the Inventory page with Inventory.htm as the file name.
8. Click an Expand control to display the initial version of the Inventory.htm page (see
Figure 25.27). Click OK to acknowledge “The DefaultSort property is invalid” message.
Removing the Navigation Controls and Adding a Category Caption
The Inventory page has only eight categories and a few products per category, so you don’t
need navigation controls on the form. If you retain the Header: GroupLevel0 section and
the Expand controls for the group, instead of expanding all groups by default, a
CategoryName caption adjacent to the Expand control aids readability.
25
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Figure 25.27
Deleting the expressions in the source
report’s text box and
changing the data
source of the text
boxes results in this
initial page design.
To make the initial design changes to the page, do this:
1. Change to Page Design view. Right-click Header: GroupLevel0, and clear the Record
Navigation check box. Do the same for the Header: qryInventory section.
2. Double-click the Expand control, click the Other tab, and change the Src property
25
value to Black
Arrow.
3. Open the Toolbox, select the Bound Span control, and draw the control adjacent to the
right of the Expand control. Delete the added label.
4. Double-click the control, click the Data tab, open the ControlSource list, and select
CategoryName.
The ControlSource property value changes to GroupOfCategoryName:
CategoryName.
5. If you want to retain the Category label and CategoryID text box in the Footer:
GroupLevel0 section, double-click the text box and set its ControlSource property to
In this case, the property value becomes GroupOfCategoryName1:
CategoryName.
CategoryName.
6. If you change the ControlSource property value of the CategoryID text box or delete it,
you must change the value of the DefaultSort property of the GroupLevel0 group properties. For this example, the original value is [GroupOfCategoryID98] ASC, but this field
no longer exists in the Field List. Right-click the section, choose Group Level
Properties, and set the DefaultSort property value to [GroupOfCategoryName] ASC.
TIP
Be sure to change the DefaultSort property when deleting or changing transformed
text boxes on which group sorting depends. If you don’t, you receive “The DefaultSort
property is invalid” messages when changing to Page view. The DefaultSort property
value must match a GroupOfFieldName item in the Field List.
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7. The offending DefaultSort property value that raises the error on expanding a group is
DESC with no field name for GroupLevel: Query Inventory. Change DESC to [Value]
DESC to fix the problem.
8. If the font name for the new controls that you’ve added isn’t the same as the existing
controls, conform the fonts in other than the Caption: GroupLevel0 section. Tahoma is
the font used for most of the examples in this book.
9. Change to Page view to check your work so far (see Figure 25.28).
Figure 25.28
Removing navigation
controls, adding a
CategoryName caption, and making
other minor changes
improve the usability
of the form.
25
Adding Category Subtotals and Grand Totals to the Page
Adding subtotals and grand totals to pages differs considerably from the method that you
use for reports. The AutoSum feature makes replacing the missing group subtotals and
grand totals easy.
To replace the report’s missing subtotals and grand totals, do the following:
1. Select the UnitsInStock text box in the Header: qryInventory section, and click
AutoSum to add a new label and SumOfUnitsInStock text box in the Footer:
GroupLevel0 section. Delete the label and the original text box, and drag the
SumOfUnitsInStock text box to the right of the Sum: label.
2. Repeat step 1 for the text box under the Value label. Move the SumOfValue text box to
the right of the Cat. Value label.
3. Delete the % Cat. and Value label and text boxes in the Footer: GroupLevel0 section.
Programming calculated text box values is beyond the scope of this chapter. Drag the
Category label and text box to the right.
4. Select the SumOfUnitsInStock text box, and click AutoSum to add a Footer:
qryInventory-SumOfUnitsInStock section and a SumOfSumOfUnitsInStock text box.
Delete the associated label. Align the left and right edges of the Footer section with the
sections above it.
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5. Repeat step 3 for the SumOfValue text box, and then adjust the positions of the text
boxes under the Units and Value text boxes.
6. Select the Grand Total: label, and press Ctrl+X to cut it to the Clipboard. Delete the
unnamed footer section where the Grand Total: label was located.
7. Select the Footer: qryInventory-SumOfUnitsInStock section, and press Ctrl+V to paste
the label. Figure 25.29 shows the final design in Page Design view.
Figure 25.29
The final design of the
Inventory.htm page
includes units and
value subtotals by
category, as well as
grand totals for all
categories.
8. Open the report in Web Page Preview to display the summary version of the page (see
25
Figure 25.30).
Figure 25.30
Web Page Preview
displays the eight
subtotals and grand
totals for units in
stock and inventory
value.
The Inventory link to the Inventory.htm page is in the Data25.mdb file located in the
\Seua11\Chaptr25 folder of the accompanying CD-ROM.
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Troubleshooting
Troubleshooting
Data Source Problems
A “Microsoft Web Components could not open the database C:\Path\FileName.mdb” message
appears when I try to open a page from another machine on the network.
The most likely cause of this problem is that you forgot to change the ConnectionString
property for the Jet 4.0 data source of the page from the default well-formed path to the
UNC \\ServerName\ShareName\FileName.mdb format. On the design computer, open the
page in Design view, right-click the page, and choose Page Properties. Click the Data tab,
select the ConnectionString property, and press Shift+F2 to open the connection string in
the Zoom box. Change the DataSource= element of the connection string to the UNC path
to the share and file.
Another possibility is that the UNC connection string is invalid or the user doesn’t have
read or read/write permissions for the share. In this case, check the capability of the client
to browse the ShareName folder named in the error message.
Parameter Naming and Cookie Parsing Problems
When I click the link on the navigation page to open a page that requires a query parameter value,
the Enter Parameters dialog opens.
The name that you supplied as the first (parameter name) argument of the
MSODSC.RecordsetDefs(“QueryName”).parametervalues.Add method statement doesn’t match
the name specified in the query design grid. If you’re query expects a conventional input
parameter, open the query in Design view, copy the [ParameterName] element to the
Clipboard, and paste it into the Script Editor. (Don’t forget to add the surrounding doublequotes.)
When I click the link on the navigation page to open a page that requires a query or filter parameter
value, the page opens with an empty Recordset.
The most likely cause of this problem is an error in the length argument of the mid function
used to parse the cookie. For example, if you substitute 9 or less for 10 in the lngLastOrder
= Mid(strCookie, InStr(strCookie, “LastOrder=”) +10) statement, the parameter value
passed to the query or filter begins with =, which is invalid for a date value. Count the number of characters in the name element of the cookie carefully to ensure that you’re passing
the correct value to the parameter.
If the preceding issue isn’t the problem, temporarily add a message box (MsgBox) statement
with the variable name as the Prompt argument. For example, to check what the preceding
line of script returns, add a MsgBox lngLastOrder statement after the line. When you’ve
diagnosed the problem, add an apostrophe (‘) in front of msgbox to comment out the statement. It’s also a good idea to add a temporary MsgBox strCookie statement to check the
crumbs while debugging your cookie-parsing code.
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Chapter 25 Converting Access Objects to Data Access Pages
In the Real World—Enhancing Data Access Page
Design
Much of the content of this chapter concentrates on the lack of support by DAP for common Access form and report designs and control objects. Observations about Save As DAP
features that work as expected might be classified as damnation by faint praise. There are
workarounds for unsupported objects—such as subforms and subreports—but most
workarounds aren’t elegant, require VBScript programming expertise, and often need additional HTML code. In most cases, what you see in Access isn’t what you get in pages without a considerable amount of work on your part. Bear in mind, however, that creating a
datasheet-style data entry Web page, for example, isn’t a piece of cake in any authoring tool.
This is especially true if you need to implement the equivalent of the Undo, Sort…, and
Filter… buttons of the navigation control.
Third-party Access developers have the opportunity to improve on the basic functionality of
the Save as DAP feature. For example, Michael Kaplan and Julianne Lee of Trigeminal
Software, Inc. (TSI) developed a Form/Report to Data Access Page Wizard that overcomes
many Save As DAP limitations. For example, the TSI Wizard handles most subforms and
subreports, which open in an inline frame (<IFRAME>), and generates working drop-down
lists (see Figure 25.31). The TSI Wizard is an Access add-in library (FrmRpt2Dap.mde) that
you can download from http://www.trigeminal.com/frmrpt2dap.asp. Installation instructions are at http://www.trigeminal.com/frmrpt2dap_readme.asp. Data25.mdb in the
\Seua11\Chaptr25 folder of the accompanying CD-ROM includes the Orders and Orders
Subform pages generated by the TSI Wizard. The pages have minor design modifications,
and the VBScript in the Orders.htm page has been altered to enable opening the subform
directly from the Orders Subform.htm file.
Figure 25.31
Trigeminal Software,
Inc.’s Form/Report to
Data Access Page
Wizard populates
combo boxes and displays subforms in an
inline frame.
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In the Real World—Enhancing Data Access Page Design
Most of Microsoft’s development investment in the upgrade from Office 2002 to Office
2003 is devoted to XML-related features. Microsoft’s promotion of the .NET Framework
for XML Web services has shifted the company’s development focus to XML file generation
manipulation by Office System 2003 members and Visual Studio .NET projects. Data access
pages rely on HTML, which has a very limited repertoire of native control objects compared to conventional Windows applications. The capability to save complex Access objects
to pages is, to a major extent, constrained by HTML 4.0 limitations. “If your only tool is
HTML, everything looks like a <TABLE>, <TEXTAREA>, or <SPAN>” oversimplifies the issue but
remains a valid aphorism.
Browser users are accustomed to crude Web-based data-entry forms and less-than-lightning
response times, but they do expect attractive, consistent page graphics. The appearance of
your pages is likely to be more important to executive and management types than their
content or performance. Web page form over function priorities of nonusers is one of the
reasons why this chapter and the preceding two chapters emphasize design changes to make
pages more attractive. If your employer has a organization-wide page layout with standard
logos, colors, fonts, and other design attributes, make sure that your DAP conform.
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