How to pass values to two different parameters

问题

I am developing a Windows Application and use a Crystal Report in it.

I am able to pass value to one parameter of Crystal Report. Now, I have added one more parameter to Crystal Report, but confused about what modification I have to make in below code.

Below code is written to pass value to one parameter of CR.

Private Sub btnLoadBatch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoadBatch.Click
    Try
        Dim cr As New crMonthwiseBatch
        Dim oBatches As New Batches

        Dim Month As Integer = dtFrom.Value.Date.Month
        Dim StartDateForBatch As Date = New DateTime(dtBatchStartFromMonth.Value.Year, dtBatchStartFromMonth.Value.Month, "1")
        Dim DaysinMonths As Integer = System.DateTime.DaysInMonth(dtBatchStartFromMonth.Value.Year, dtBatchStartFromMonth.Value.Month)
        Dim EndDateForBatch = StartDateForBatch.AddDays(DaysinMonths)

        oBatches.LoadByQuery("CreatedDate >= #" + StartDateForBatch + "# and CreatedDate <= #" + EndDateForBatch + "#")
        cr.SetDataSource(oBatches)

        Dim crParameterFieldDefinitions As ParameterFieldDefinitions
        Dim crParameterFieldDefinition As ParameterFieldDefinition
        Dim crParameterValues As New ParameterValues
        Dim crParameterDiscreteValue As New ParameterDiscreteValue

        crParameterDiscreteValue.Value = "Batch List of Month - " + MonthName(dtBatchStartFromMonth.Value.Month) + " " + dtBatchStartFromMonth.Value.Year.ToString
        crParameterFieldDefinitions = cr.DataDefinition.ParameterFields
        crParameterFieldDefinition = crParameterFieldDefinitions.Item("MonthName")
        crParameterValues = crParameterFieldDefinition.CurrentValues

        crParameterValues.Clear()
        crParameterValues.Add(crParameterDiscreteValue)
        crParameterFieldDefinition.ApplyCurrentValues(crParameterValues)

        CrystalReportViewerMonthwiseBatch.ReportSource = cr
        CrystalReportViewerMonthwiseBatch.Refresh()
    Catch ex As Exception

    End Try
End Sub

回答1:

You can achieve it this way (look for comments above statement(s) for description)

Approach 1:

'...
'collection of objects for every parameter field
Dim crParameterFieldDefinitions As ParameterFieldDefinitions
'represent a parameter field
Dim crParameterFieldDefinition As ParameterFieldDefinition
'collection of ParameterValue objects for every parameter field
Dim crParameterValues As New ParameterValues()
'for retrieving and setting discrete value parameters
Dim crParameterDiscreteValue As New ParameterDiscreteValue()

'get parameters collection in current crystal report
crParameterFieldDefinitions = cr.DataDefinition.ParameterFields

'adding FIRST parameter
'get the parameter in the current report and assign a value
crParameterFieldDefinition = crParameterFieldDefinitions("PARAM_1_NAME")
crParameterDiscreteValue.Value = "PARAM_1_VALUE"
crParameterValues = crParameterFieldDefinition.CurrentValues

'clear old/default values assigned to current parameter, add and apply new value
crParameterValues.Clear()
crParameterValues.Add(crParameterDiscreteValue)
crParameterFieldDefinition.ApplyCurrentValues(crParameterValues)
'finished adding FIRST parameter

'adding SECOND and subsequent parameters
'reset the collections
crParameterDiscreteValue = New ParameterDiscreteValue()
crParameterValues = New ParameterValues()

'get parameter, assign values, clear old values, add to collection and apply
crParameterFieldDefinition = crParameterFieldDefinitions("PARAM_2_NAME")
crParameterDiscreteValue.Value = "PARAM_2_VALUE"
crParameterValues = crParameterFieldDefinition.CurrentValues
crParameterValues.Clear()
crParameterValues.Add(crParameterDiscreteValue)
crParameterFieldDefinition.ApplyCurrentValues(crParameterValues)
'finished adding SECOND parameter
'...
'Just display the report

Approach 2:
If you have multiple parameters it can also be achieved by using a separate procedure such as

Private Sub SetParams(crRpt As CrystalDecisions.CrystalReports.Engine.ReportDocument, strParamName As String, strParamValue As String)
   For Each pfField As CrystalDecisions.CrystalReports.Engine.ParameterFieldDefinition In crRpt.DataDefinition.ParameterFields
      If pfField.Name.ToString().ToLower() = strParamName.ToLower() Then
         Try
            Dim crParameterValues As New CrystalDecisions.Shared.ParameterValues()
            Dim crParameterDiscreteValue As New CrystalDecisions.Shared.ParameterDiscreteValue()
            crParameterDiscreteValue.Value = strParamValue
            crParameterValues = pfField.CurrentValues
            crParameterValues.Clear()
            crParameterValues.Add(crParameterDiscreteValue)
            pfField.ApplyCurrentValues(crParameterValues)
         Catch ex As Exception
            'add your exception handling mechanism here
            MessageBox.Show(ex.Message)
         End Try
      End If
   Next
End Sub

The above routine can be called for any report object (as cr in example below) to add any number of parameters to the reports

SetParams(cr, "@Param_1_Name", "Param_1_Value")
SetParams(cr, "@Param_2_Name", "Param_2_Value")
'...
SetParams(cr, "@Param_n_Name", "Param_n_Value")

来源：https://stackoverflow.com/questions/33127714/how-to-pass-values-to-two-different-parameters