Using ReadRecords

When using the SetDataSource method, be aware that the method will fail if your Recordset or Resultset object goes out of scope. For example, consider the following code:

Dim Report As New CrystalReport1

Private Sub Form1_Load()

Call SetData

CRViewer1.ReportSource = rpt

CRViewer1.ViewReport

End Sub

Private Sub SetData()

Dim rs As New ADOR.Recordset

rs.Open “Select * From Customer”, “Xtreme sample data” rpt.Database.SetDataSource rs

End Sub

In this example, although the rpt object is global (for the Form), the rs object exists only for the life of the SetData procedure. Even though it is assigned to the rpt object before SetData finishes, the object, and the data, that rs represents goes out of scope and is invalid for the Load event. Thus, the code will fail.

This problem can be solved using the ReadRecords method. ReadRecords forces the report to read the records into the report so that they are internal to the Report object itself rather than remaining as a separate Recordset object referenced by the report. Normally, this process would not happen until the report is displayed in the viewer using the ViewReport method.

Private Sub SetData()

Dim rs As New ADOR.Recordset

rs.Open “Select * From Customer”, “Xtreme sample data” rpt.Database.SetDataSource rs

rpt.ReadRecords End Sub

Passing fields in the correct order

When defining a Recordset or Resultset object to pass to your report, you must pay attention to the order in which the fields are added to the recordset. Fields must appear in the recordset in the same order in which they have been added to your report. In addition, all fields that appear in a data source should be included in the recordset, whether or not they are actually used in the report. For more information on

Consider a report designed using the following fields from a Data Definition file:

●Customer ID

●Customer Name

●Last Year’s Sales

Now, assume the Data Definition file was originally created with all of the following fields:

●Customer ID

●Customer Name

●Contact First Name

●Contact Last Name

●Contact Title

●Contact Position

●Account Manager

●Last Year’s Sales

●Address1

●Address2

●City

●Region

●Country

●Postal Code

●Phone

●Fax

When you create a new recordset, if you only add the three fields that appear in your report, values for one or more fields may be missing. You must, instead, include the three fields in your report in the order that they appear in the Data Definition file, along with any fields that may appear between them. Thus, to correctly display Customer ID, Customer Name, and Last Year’s Sales in your report, you must design the new recordset using all of the following fields:

●Customer ID

●Customer Name

●Contact First Name

●Contact Last Name

●Contact Title

●Contact Position

●Account Manager

●Last Year’s Sales

In fact, you may want to get in the habit of designing your runtime recordsets so that they include all fields from the original Data Definition file. This can save time later if you make changes to the report.

Working with secure data in reports

If your report connects to a secure data source that requires log on information, you will not be able to log off of the data source until the Report object has been closed or gone out of scope. Keep in mind that if you assign the Report object to the ReportSource property of the CRViewer object in the Seagate Crystal Reports Smart Viewer, the Report object can not be closed until you assign a new value to the Smart Viewer or close the CRViewer object. Thus, you will not be able to log off of a secure data source until the report is no longer displayed in the Smart Viewer.

Handling the Format event

The Seagate Crystal Report Designer Component provides a Format event for every section of your report. This allows you to dynamically control report formatting and output at runtime. For example, conditional formatting can be applied during the Format event, based on conditions that exist only at runtime.

The Format event is a standard Visual Basic event that can be programmed by displaying the Code View of the Report Designer Component. Assuming the Report Designer has been named CrystalReport1 in your Visual Basic project:

1In the Visual Basic Project window, select the CrystalReport1 designer from the Designers folder.

2Click the View Code button in the toolbar at the top of the Project window. A Code window will appear for the CrystalReport1 designer component.

3In the object drop-down list box at the top left of the Code window, select a Section object that you want to apply code to. Notice that Section objects are numbered in the order that they appear on your report, from the top of the Report Design window to the bottom. For instance, if you select the Section1 object, your code will apply to the Report Header section of your report. These Section objects are labeled for you at the top of each section in the Report Designer window.

Notice that when you select a Section object, the Format event is automatically selected for you in the event drop-down list box at the top right of the Code window. Format is the only event available to the Section object.

When writing code for the Format event, keep in mind that not all properties and methods for all objects are available during the Format event. Many properties are available on a read-only basis. If you are not sure about a property or method, refer to the specific property or method name in the Report Designer Object Model reference section of this Help file.

The Format event receives a single argument from the Report Designer Component. The pFormattingInfo argument is an object of type FormattingInfo. The FormattingInfo object has only three properties:

●IsEndOfGroup - This property is true if the section being formatted is a Group Footer.

●IsRepeatedGroupHeader - This property is true if the section being formatted is a repeated Group Header. Repeated Group Headers appear when a group extends to two or more pages, and the group has been formatted to repeat information that appears in the Group Header on the second, third, etc. pages. This property is only true if the Group Header is the second, third, etc. instance of the Group Header. It is false for the original first instance of the Group Header.

●IsStartOfGroup - This property is true if the section being formatted is a Group Header.

When designing your application, be aware that when a section is being formatted, all objects in that section are also being formatted. Also, all other sections and objects outside of the current section are not being formatted. This information can affect how data is displayed in various sections of the report, depending on your code.

Calculating Results

If you are using the Format event to calculate values, do not perform any calculations which require the values to be carried across sections. For example, if you want to display a value in a Text object for the first record in the Details section, add a value to the first value, and display the results for the next record, the result may be incorrect. (This process is known as a running total.)

It is possible for the Format event to be fired multiple times for a section, each time the report is displayed. Whether or not this happens depends on the contents of the section, groupings in the report, and various other common report features. For this reason, a calculation performed in the Format event, may be performed several times before final display, resulting in invalid results if the calculation is dependent on a value created in another record or section.

In general, the Format event should be used primarily for formatting the report. Calculations can be performed, as long as they do not depend on assigning a value to an outside variable or receiving a value from an outside variable. For example, you could evaluate the value of a field in the section, then display a flag based on its value. If Sales values drop below a minimum quota, for instance, they could be displayed in red with a warning message next to them.

Changing the contents of a Text object

Text objects are a common feature of reports designed in the Seagate Crystal Report Designer Component, and the Report Designer Object Model allows you to manipulate those objects at runtime. Use Text objects to simply display information inside a report, or use them to perform complex calculations in Visual Basic and display the results in your report.

Reports can be customized at runtime based on user input, and a Text object may be a simple way of personalizing the data based on your users’ input. Alternately, you may need to leverage the full power of Visual Basic to perform complex operations on database data. The results of such calculations can easily be assigned to a Text object at runtime to produce data that could not be displayed any other way. Only the Seagate Crystal Report Designer Component gives you all of the power of Visual Basic for your reports in a single simple straightforward object.

The following example changes the contents of a Text object during the Load event of the Form containing the Crystal Smart Viewer ActiveX control. This is especially important if the value of your text object is dependent on data in your data source. Since this is also a common place to change the data source used by a report, changing values in Text objects during the Load event often becomes convenient.

Private Sub Form_Load()

Dim Report As New CrystalReport1 ‘ More code here

Report.Text1.SetText “Here is some text from my app” CRViewer1.ReportSource = Report

CRViewer1.ViewReport End Sub

Notice that the SetText method is used to apply a new value. The Text property of the object model’s TextObject object is a read-only property, a convenient shortcut to get information about the existing value. However, SetText must be used to assign a new value.

The example above simply assigns a string to the Text1 object in the report. A more complicated technique may be to access data in a database and calculate a new value in Visual Basic, then display that value through a Text object on the report. In such cases, you could design your report in the Report Designer Component design window to specifically supply a Text object for such a result. The following code demonstrates this technique:

Private Sub Form_Load()

Dim maxValue As Currency

Dim maxValueString As String

Dim Report As New CrystalReport1

Dim rs As New ADODB.Recordset

rs.Open “SELECT * FROM Customer”, _ “DSN=Xtreme sample data;”, adOpenKeyset

Report.Database.SetDataSource rs

maxValue = 0

rs.MoveFirst

Do While Not rs.EOF

If rs.Fields(“Last Year’s Sales”) > maxValue Then

maxValue = rs.Fields(“Last Year’s Sales”)

End If

rs.MoveNext

Loop

maxValueString = “The maximum value is “ & _ Format(maxValue, “Currency”)

Report.Text1.SetText maxValueString

CRViewer1.ReportSource = Report

CRViewer1.ViewReport

End Sub

In this example, we are finding the maximum value of the Last Year’s Sales field of the new data source, formatting that value as Currency, then displaying a message containing the value through a Text object on the report. As you can see, Text objects provide many options for controlling the output of data in your reports.