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How to Programmatically Load a Report

You won't normally load reports from the My Documents\ Visual Studio Projects folder on an end user's computer, and the login information and database location are normally different when you deploy a report. For this reason, you must be able to load a report dynamically and set login information at runtime.

Using the TableLogOnInfo class of the CrystalDecisions.Shared namespace, you have programmatic access to the login information for the database tables in a report. Using the ReportDocument class, you can specify a report to load at runtime.

In your applications, you should have a single form named rptViewer that has the report viewer control. The report name that the user is requesting is passed in the constructor for the frmViewer. It's a good idea to have a folder named Reports in your solution where all the reports are located, so you can use the relative path of the report to load at runtime.

The code in Listing 18.1 can be added to either the Load event of the frmViewer or after the InitializeComponent call in the form's constructor. After calling the Load method on the ReportDocument object, you set the ConnectionInfo properties by looping through the Tables collection that exists in the report. To tell the viewer what to load, you simply set the ReportSource property just as you did in the properties window for the viewer.

Example 18.1. Loading a Crystal Report in Code

Private Sub rptViewer_Load(ByVal sender As System.Object, _
   ByVal e As System.EventArgs) Handles MyBase.Load

  Me.Cursor = Cursors.WaitCursor

  Try

  Dim oRpt As New ReportDocument()
  oRpt.Load("..\Reports\" & strReportName)

  Dim tbCurrent As CrystalDecisions.CrystalReports.Engine.Table
  Dim tliCurrent As CrystalDecisions.Shared.TableLogOnInfo

  For Each tbCurrent In oRpt.Database.Tables
    tliCurrent = tbCurrent.LogOnInfo
    With tliCurrent.ConnectionInfo
      .ServerName = "jb1gs"
      .UserID = "sa"
      .Password = ""
      .DatabaseName = "Northwind"
    End With

    tbCurrent.ApplyLogOnInfo(tliCurrent)

  Next tbCurrent

  viewer.ReportSource = oRpt

  Catch ex As Exception
    MsgBox(ex.Message)
  Finally
    Me.Cursor = Cursors.Default
  End Try

End Sub

private void frmViewer_Load(object sender, System.EventArgs e)
{

CrystalReport1 oRpt = new CrystalReport1 ();
Database oDb;
Tables oTables;
Table oTable;
TableLogOnInfo tliCurrent;
ConnectionInfo oCnInfo = new ConnectionInfo ();

// Setup the connection information structure to be used
// to log onto the datasource for the report.
oCnInfo.ServerName = "jb1gs";
oCnInfo.DatabaseName = "Northwind";
oCnInfo.UserID = "sa";
oCnInfo.Password = "admin";

//Get the table information from the report
oDb = oRpt.Database;
oTables = oDb.Tables;

//Loop through all tables in the report and
// apply the connection
//information for each table.
for (int i = 0; i < oTables.Count; i++)
{
   oTable = oTables [i];
   tliCurrent = oTable.LogOnInfo;
   tliCurrent.ConnectionInfo = oCnInfo;
   oTable.ApplyLogOnInfo(tliCurrent);
}

crystalReportViewer1.ReportSource = oRpt;
}

After the ConnectionInfo properties and the ReportSource are set, the report will display in the viewer.

Printing a Report Without the Viewer Control | Next Section

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