While exporting crystal report, if u've mutiple values for one parameter fild of CR, u can use following code,
it's working fine........




Private Function SetParameterVal()

    Dim paramField As New ParameterField

    '''******** Get the parameter values in a data reader **********'''

        strDr = object1.GetSelectedYearDataReader(Year)

    '''******** Put it in a while-loop **********'''


        While strDr.Read


            discreteVal = New ParameterDiscreteValue '''' ******* Put this line to avoid over-writing *******''''

            discreteVal.Value = (strDr(0)) '''' ******* Set the DR value to ur discrete-value *******''''

            paramField.CurrentValues.Add(discreteVal) '''' ******* Add it to parameter fied ( b-coz it can store multiple values ) *******''''

            crReportClass.SetParameterValue(0, paramField.CurrentValues) '''' ******* Set that value to ur desire index no. *******''''


        End While



 End Function

Nikhil