accessing crystal report parameter

[saadabc]

i have a crystal report that is running off a SQL Server stored procedure. The stored procedure takes 3 parameters. when i add the stored procedure in the crystal report - the parameters automatically appear in the report (under Parameter fields) .... as

@database
@fromdate
@todate



now when i try to set the parameters in vb .net using this code:



Dim paramFields As ParameterFields
paramFields = crReportViewer.ParameterFieldInfo
Dim paramField As New ParameterField
Dim curValues As ParameterValues = paramField.CurrentValues
Try
paramField = paramFields("@database")

Catch ex As Exception
MsgBox(ex.ToString)
End Try

Dim discreteValue As ParameterDiscreteValue = New ParameterDiscreteValue

discreteValue.Value = ReportCriteria


I get an error:

"Object Reference Not Set to An Instance of an object" at the line:

paramField = paramFields("@database")

 

[techsmith]

Try 
  paramField = paramFields.Item("@database")
Catch ex As Exception
  MsgBox(ex.ToString)
End Try

Although the '@' prefix suggests that your looking at a formula field rather than a parameter.

Hope this helps

 

[SHelton]

The following has always worked for me:

Dim cr As New CrystalDecisions.CrystalReports.Engine.ReportDocument

cr.Load("C:\Test.rpt")

Dim pv As New CrystalDecisions.Shared.ParameterValues

Dim pdv As New CrystalDecisions.Shared.ParameterDiscreteValue

pdv.Value = <insert parameter value here, can be any type>

pv.Add(pdv)

cr.DataDefinition.ParameterFields("@database").ApplyCurrentValues(pv)

Note that if you want to pass a null value to a Crystal parameter, you should use Nothing, not DBNull.Value.