Access Cookbook, 2nd Edition [Electronic resources] نسخه متنی

Recipe 3.11 Make a Vertical Line the Same Height as a CanGrow/CanShrink Control

3.11.1 Problem

You have a control on a report
that has its CanShrink and CanGrow properties set to Yes so it can
grow or shrink to accommodate different amounts of text. You placed a
vertical line to the left of the control, and you want it to be the
same height as the control. Is there a way you can synchronize the
height of the two controls?

3.11.2 Solution

If you
place a line on a report using the Line tool, it will always be the
same size. To make a line change its height to match the height of
another control (or group of controls), you need to use the Line
method in a procedure attached to the Print event of a report
section. This solution uses the Line method to make a line whose
height varies to accommodate the changing height of a text box that
displays a memo field.

Follow these steps to add to your own report a vertical line that
shrinks or grows to match one or more CanShrink/CanGrow controls in a
section:

1. Create a report or open an existing report in design view.
   Don't use the Line control to create a vertical line
   in the report. If you've already created such a
   line, remove it now.

2. Create an event
   procedure for the Print event of the group footer section (or the
   section on your report where you'd like the line to
   appear). (For more information on creating event procedures, see this
   book's Preface.) In the event procedure, add code
   similar to this:

   Private Sub GroupFooter0_Print(Cancel As Integer, PrintCount As Integer)
   Dim sngLineTop As Single
   Dim sngLineLeft As Single
   Dim sngLineWidth As Single
   Dim sngLineHeight As Single
   Const acbcSMTwips = 1
   Const acbcDSSolid = 0
   Me.ScaleMode = acbcSMTwips
   Me.DrawStyle = acbcDSSolid
   ' Set the coordinates for the line.
   sngLineTop = Me.lblConditions.Top
   sngLineLeft = 0
   sngLineWidth = 100
   With Me.txtConditions
   sngLineHeight = .Top + .Height
   End With
   ' Draw the line.
   Me.Line (sngLineLeft, sngLineTop)-Step(sngLineWidth, sngLineHeight), , BF
   End Sub

   Replace the references to lblConditions and txtConditions with the
   names of the controls in your own report.

3. Save and preview the report to verify that the line alongside the
   CanShrink/CanGrow controls changes, as in Figure 3-27. The completed sample report is shown in
   design view in Figure 3-25.

Figure 3-25. rptBusinessAddresses2 in design view

To see an example of this solution, load

03-11.MDB . Open rptBusinessAddresses1 in preview
view (Figure 3-26). This report lists business
addresses and contract conditions. Notice that the line in the
company footer section is of fixed height and does not vary to match
the height of this section.

Figure 3-26. This report contains a fixed-height line next to a variable-height text box

Now open rptBusinessAddresses2 in preview view (Figure 3-27). This version of the report contains a line
whose height matches the height of the company footer section.

Figure 3-27. A report with a programmatically created variable-length line

3.11.3 Discussion

The event procedure uses the Line
method to create a line that starts at the top of the lblConditions
label and extends to the bottom of the txtConditions text box,
growing and shrinking in proportion to the text box. You can use the
Line method to draw lines or rectangles on reports using the
coordinates you specify (sngLineHeight through sngLineWidth in the
sample procedure). The event procedure sets the sngLineTop argument
to the top of the lblConditions label, sngLineLeft to 0, sngLineWidth
to 100, and sngLineHeight to the bottom of the txtConditions text
box. Because Access does not provide a VBA Bottom property for
controls, this value is calculated by adding the text
box's Height property to its Top property, using the
following piece of code (which makes use of the VBA
With...End With construct):

With Me.txtConditions
sngLineHeight = .Top + .Height
End With

The line itself (actually, a rectangle) is drawn by the following
line of code:

Me.Line (sngLineLeft, sngLineTop)-Step(sngLineWidth, sngLineHeight), , BF

where the variables in the first set of parentheses define the
upper-left corner of the rectangle and those in the second set of
parentheses define its width and height. The reserved word Step
allows you to use height and width values for the rectangle instead
of specifying the lower-right corner. The last argument, BF,
indicates that the line will be a rectangle (B) instead of a line and
that it will be filled with the same color as its border (F).

The ScaleMode property specifies
the unit of measurement. Because Access uses twips as its measurement
unit, this property is generally set to twips, as in the
acbcSMTwips constant in the sample code. The
available settings are listed in Table 3-9.

The DrawStyle property specifies the
line type; it is set to Solid in the sample code using the
acbcDSSolid constant. The available settings are
listed in Table 3-10.