The new WPF viewer control to use in your windows
applications is a slick new control. It looks better and has some newer
features, as revealed in the API section above. As of Beta 2, binding a report
to the viewer is done most easily programmatically.
If you want to allow the end user some control of what
report to view, enable the property ShowOpenFileButton to allow the user to
select a report. Eventually there will be a property to set this, but you can
set the report to an embedded resource using code. For instance, in example 1,
the code shows how to bind an embedded resource to the report viewer.
CrystalReport1 is a report created in a project. To bind
this report to the new WPF viewer, use the property ViewerCore.ReportSource and
set it to the instance of the embedded report. Code Sample 1 shows the code.
Listing 1
InitializeComponent();
reportViewer.Owner = this;
CrystalReport1 newCR = new CrystalReport1();
reportViewer.ViewerCore.ReportSource = newCR;
Figure 1: Sample of viewer
The new
control does have better graphics. Besides better graphics the viewer also has
built in performance benefits. When filtering, if the data is not changed, the
data does not get refreshed.
For
instance, if you use a parameter to hide or show an object on your report, the
data would not be affected. In the report shown in Figure 1, there is a print
date that shows at the top of the report. An object like this would be perfect
to demonstrate the new refreshing strategy.
First, edit
the report. Add a parameter, named ShowPrintDate. Make that parameter Boolean
and set the default value to True. Select the object containg print date, and
open the format properties dialog box. On the common tab, select the formula
button beside the suppress checkbox. In that formula box, enter the formula
shown in code sample 2.
Listing 2
IIF ({?ShowPrintDate},False ,true )That formula will allow you to toggle visibility of the
print object on the report. When you select and change that parameter, the
report will not go back to the data store to refresh the data. If you utilize
these types of dynamic parameters in your reports, you should see some
performance gains from this.
