passing parameter in crystal report

how do i pass the parameter set in crystal report to the form.. for example.. i have a combobox and a report..so how do i choose the item in the combobox and redirect it to the report.. heres how i did it but doesn't works..

Dim pvCollection As New CrystalDecisions.Shared.ParameterValues()
Dim pdvdept As New CrystalDecisions.Shared.ParameterDiscreteValue()
Dim rptCrystalReport3 As New ReportDocument()

' In this event the Ten Most Expensive Products Report is loaded
' and displayed in the crystal reports viewer.

' Objects used to set the proper database connection information
Dim tbCurrent As CrystalDecisions.CrystalReports.Engine.Table
Dim tliCurrent As CrystalDecisions.Shared.TableLogOnInfo

' Create a report document instance to hold the report

Try

' Load the report
rptCrystalReport3.Load("..\CrystalReport3.rpt")

' Set the connection information for all the tables used in the report
' Leave UserID and Password blank for trusted connection

' Set the discreet value to the customers name.
pdvdept.Value = ComboBox1.Text <<<<----------(I STILL CAN CHOOSE FROM THE COMBOBOX)

' Add it to the parameter collection.
pvCollection.Add(pdvdept)

' Apply the current parameter values.
rptCrystalReport3.DataDefinition.ParameterFields("@dept").ApplyCurrentValues(pvCollection)

' Hide group tree for this report
CrystalReportViewer1.DisplayGroupTree = False

' Set the report source for the crystal reports viewer to the
' report instance.
CrystalReportViewer1.ReportSource = rptCrystalReport3

' Zoom viewer to fit to the whole page so the user can see the report
CrystalReportViewer1.Zoom(2)

Catch Exp As LoadSaveReportException
MsgBox("Incorrect path for loading report.", _
MsgBoxStyle.Critical, "Load Report Error")

Catch Exp As Exception
MsgBox(Exp.Message, MsgBoxStyle.Critical, "General Error")

End Try

Can anyone help me..its kinda urgent! :confused: :rolleyes: