Wrox Professional Crystal Reports for Visual Studio NET Second Edition phần 5 pdf

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Chapter 4

Speaking of different types of users, the next section deals with how to customize the appearance and

layout of the viewer itself. So in addition to showing them only the records they want to see, you could

also give them their own custom viewer with which to view the resulting report.

Customizing the Appearance and

Behavior of the Report Viewer

The CrystalReportViewer class contains all of the properties, methods, and events that relate to the

viewer itself, its appearance, the methods that are used to make the viewer perform certain actions (like

refresh or print a report), and events that can be used to determine when a particular event (such as

drill-down or refresh) has occurred. To start learning how to work with the viewer, we are going to start

with the basic properties and move on from there.

When previewing your report, you may notice that there is a standard set of icons and layout that

appears on your viewer by default, but you can control most of the aspects of the viewer by setting a few

simple properties for the Crystal Report Viewer in the Properties window, as shown in Figure 4-16.

Figure 4-16

The area at the top of the viewer is the toolbar, which can be shown or hidden as an entire object, or you

can choose to only show certain icons. On the left-hand side is a Group Tree, generated by the grouping

that you have inserted into your report. The properties that control these general properties are Boolean

and are listed below:

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Report Integration for Windows-Based Applications

Property Description

DisplayBackgroundEdge For showing the off-set edge around your report when

previewing

DisplayGroupTree For showing the group tree on the left side of the viewer

DisplayToolbar For showing the entire toolbar at the top of the viewer

All of these properties default to True and you cannot change the position of any of these elements; they

are fixed in place on the viewer. You can, however, hide the default toolbar and create your own buttons

for printing, page navigation, and other functions, and we’ll look at that a little later in the chapter.

For the icons within the toolbar, you can also set simple Boolean properties to show or hide a particular

icon, as shown here:

❑ ShowCloseButton

❑ ShowExportButton

❑ ShowGotoPageButton

❑ ShowGroupTreeButton

❑ ShowPageNavigateButtons

❑ ShowRefreshButton

❑ ShowTextSearchButton

❑ ShowZoomButton

❑ ShowPrintButton

So a typical use of these properties is where you want to give users a view-only preview, with no printing or

exporting options and no option to refresh the report. Going back to our original report (ch4_worldsales),

we could easily set a few properties before you set your ReportSource property to make this happen.

Double-click anywhere on your form to open the code view and in the form’s Load method, enter the

following:

...

End With

myTableLogonInfo.ConnectionInfo = myConnectionInfo

myTableLogonInfo.TableName = “customers”

myTableLogonInfos.Add(myTableLogonInfo)

CrystalReportViewer1.LogOnInfo = myTableLogonInfos

CrystalReportViewer1.ReportSource = myReport

CrystalReportViewer1.DisplayGroupTree = False

CrystalReportViewer1.ShowExportButton = False

CrystalReportViewer1.ShowRefreshButton = False

CrystalReportViewer1.ShowPrintButton = False

CrystalReportViewer1.ReportSource = New ch4_worldsales_northwind()

End Sub

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Chapter 4

When the report is previewed, it will appear as shown in Figure 4-17.

Figure 4-17

Keep in mind that you can set these properties any time prior to the report preview. You could store indi￾vidual user or security settings in your application data and then set the appropriate properties prior to

viewing the report. This is just one example of where we can customize how a report is presented to the

user; the next section on the methods available within the viewer takes that discussion one step further.

Viewer Methods

When working with the Crystal Report Viewer, we have a number of methods available to us, which

will allow us to integrate specific viewer functions into our application. As we move through this

section, keep in mind that these methods can be used to create your own look and feel for the report

preview window, as shown in Figure 4-18.

During the course of this section, we will actually be looking at the code behind the custom viewer

shown here, so it is probably not a bad idea to start a new project within this chapter’s solution file. To

create a new project from within Visual Studio, select File → New → Project and from Visual Basic

Projects, select Windows Application and specify a name, as shown in Figure 4-19, (in the sample code,

we have called this project viewer_methods) and location for your project files. Remember to set this

project as your startup project.

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