Writing a Viewer Utility for Crystal Reports
page 2 of 3
by Julia Lerman
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A  Complete Viewer Utility

The Crystal Viewer utility is made up of two Windows Forms. The first form, shown in Figure 1, lists available reports in a ListBox for the user to select from while the second (ReportViewer) hosts the CrystalViewer control to display the selected report.


Figure 1 - The Viewer Utility displays available reports in a specific path. The user can hide the two settings if they wish.


When the user selects an item from the list, the utility loads the chosen file using the Load method shown above, then establishes the connection to the database as described above using the value stored in the Database Server field. The ReportDocument is then passed to the ReportViewer form which attaches the report to the CrystalViewer using the DataSource property. Lastly, the main form calls the ReportViewer form’s Show method. If parameters are required, Crystal Reports automatically opens its own form for collecting the necessary values and then the report is displayed.  Parameters are discussed in more detail later in this article.


Figure 2 - If the report has parameters, Crystal Reports' "Enter Parameter Values" form will be displayed.


The utility will need to know where to look for saved reports and the name of the database server. These are stored using .NET’s ApplicationSettings and the end-user has the ability to update those values using the settings fields at the bottom of the form.  ApplicationSettings can be created in the Settings page of the project Properties as shown in Figure 3, and then accessed in code. If a user modifies these settings, they will be persisted in the application.


Figure 3 - The Viewer Utility has two application settings, ReportLocation and Server, which can be defined in the Project Properties window.


When the form loads, the ListBox is populated using the following method:

  Private Sub FillReportList()
      Dim FileList As New ArrayList
      Dim files() As String = Directory.GetFiles(My.Settings.ReportLocation)
      Dim f As FileInfo
      For Each filepath As String In files
        f = New FileInfo(filepath)
        If f.Extension = ".rpt" Then
        End If
      ListBox1.DataSource = FileList
      btnRunReport.Enabled = (FileList.Count > 0)
    Catch ex As DirectoryNotFoundException
      MessageBox.Show("Report Locations folder is invalid. " & _
      "Please edit in Settings.")
    Catch ex As Exception
      MessageBox.Show("Report List cannot be loaded.")
    End Try
   End Sub

The ellipses button to the right of the Report Location on the form opens a FolderBrowserDialog to assist the user in selecting a folder path. Drag a FolderBrowserDialog component onto the form to use this functionality. The following code opens up the FolderBrowserDialog then stores the resulting path to the user setting.  If the user changes the path, then the ListBox is repopulated and the setting is remembered the next time the user runs the application.

    With FolderBrowserDialog1
      .SelectedPath = ReportLocation.Text
      If .SelectedPath <> ReportLocation.Text Then
        My.Settings.ReportLocation = .SelectedPath
        ReportLocation.Text = .SelectedPath
      End If
    End With

The Database Server field is a textbox which the users can type in. The user setting for the database is modified in the same manner as the ReportLocation setting. A more advanced version of the Crystal Viewer utility leverages the System.Data.Sql.SqlDataSourceEnumerator class to assist the end-user in selecting an available SQL Server.

When the user selects a report and clicks the Run Report button, the following code is executed to load the report, set the connection and run the report.

  Private Sub btnRunReport_Click(ByVal sender As System.Object, _
  ByVal e As System.EventArgs) Handles btnRunReport.Click
    rptDoc = New CrystalDecisions.CrystalReports.Engine.ReportDocument
    rptDoc.Load(My.Settings.ReportLocation & "\" & _
    ListBox1.SelectedValue.ToString.Trim & ".rpt")
      With rptDoc.DataSourceConnections(0)
        Dim dbname As String = .DatabaseName
        Dim integrated As Boolean = .IntegratedSecurity
        .SetConnection(My.Settings.Server, dbname, integrated)
      End With
      Dim frm As New ReportViewer
    Catch ex As CrystalDecisions.CrystalReports.Engine.DataSourceException
      MessageBox.Show("There was a datasource error loading " & _
      "this report. Please check the Server setting.")
    Catch ex As Exception
      MessageBox.Show("There was an error loading this report. " & _
      "The error is coming from the report, not the datasource. " & _
      "Please check with the creator of the report you are trying to view.")
    End Try
  End Sub


The ReportViewer form has a SetReport method which is called in the above code before returning to call the Show method of the ReportViewer form.


Public Sub SetReport(ByVal rptDoc As _
  CrystalReportViewer1.ReportSource = rptDoc
End Sub


Figure 4 displays a form which was generated at run time using a parameter value entered by the end-user.

Figure 4 - This report was dynamically created using a parameter entered at run-time.


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