看起来非常接近......我就是这样做的（VS2010）。

  Dim  crDoc  As  CrystalDecisions.CrystalReports.Engine.ReportClass 
昏暗的pan> pvParamValue 作为 新 CrystalDecisions。共享 .ParameterValues 
 Dim  pdvParamDiscreteValue  As   New  CrystalDecisions。共享 .ParameterDiscreteValue 

 crDoc =  new  CRYSTALREPORTNAME 

 pdvParamDiscreteValue.Value = FIELDNAME.tostring 
 pvParamValue.Add（pdvParamDiscreteValue）
 crDoc.DataDefinition.ParameterFields（  @ P_PARAMETERNAME）。ApplyCurrentValues（pvParamValue）

试试这个.......... 。







Private Sub btn_save_print_Click（ByVal sender As System.Object，ByVal e As System.EventArgs ）处理btn_save_print.Click



Dim obj As New Letter_print





obj.Code = txt_code.text

obj.doc_nm = txt_doc_name.Text

obj.address = txt_address.Text



obj.ShowDialog（Me）



结束子



公共类_Print

Public CodeAs String =

公共doc_nm As String =

公共地址As String =





Private Sub Letter_Print_Load（ByVal sender As System.Object， ByVal e As System.EventArgs）处理MyBase.Load

Dim k作为新的Letter_report



k.SetParameterValue（code1，code



k.SetParameterValue（doc_nm1，doc_nm）

k.SetParameterValue（address1，地址）





CrystalReportViewer1.ReportSource = k



End Sub

End Class

 CrystalReportViewer1.Refresh（）
 Dim  rpt  As  新 ReportDocument 
 rpt.FileName =   c：\Users\sandy\BCA\CBT\result2.rpt 
 Dim  paramDV  As  新 ParameterDiscreteValue（）
 paramDV.Value = LoginForm.UsernameTextBox.Text 
 rpt.Refresh （）
 Dim  paramfields  As  ParameterFields =  Me  .CrystalReportViewer1.ParameterFieldInfo 
 Dim  param  As  新 ParameterField 
 Dim 参数 As  新 ParameterFields 
 param.Name =   result 
 Dim  param_value  As  新 ParameterDiscreteValue 
 param_value.Value = LoginForm.UsernameTextBox.Text 
 param.CurrentValues.Clear（）
 param.CurrentValues.Add（ param_value）
 params.Add（param）
 CrystalReportViewer1.ParameterFieldInfo = params 
 rpt.Refresh（）
 CrystalReportViewer1.ReportSource = rpt 
 CrystalReportViewer1.ReuseParameterValuesOnRefresh = 真跨度> 

I had tried the following code but its not working.
what should i have to chnges in the code?

code on the form1 that have crystalreportviewer1.
CrystalReportViewer1.Refresh()
Dim paramfields As ParameterFields = Me.CrystalReportViewer1.ParameterFieldInfo
Dim param As New ParameterField
param.Name = "result"
Dim param_value As New ParameterDiscreteValue
param_value.Value = LoginForm.UsernameTextBox.Text
param.CurrentValues.Add(param_value)
paramfields.Add(param)
CrystalReportViewer1.Refresh()

Looks pretty close... This is how I do it (VS2010).

Dim crDoc As CrystalDecisions.CrystalReports.Engine.ReportClass
Dim pvParamValue As New CrystalDecisions.Shared.ParameterValues
Dim pdvParamDiscreteValue As New CrystalDecisions.Shared.ParameterDiscreteValue

crDoc = new CRYSTALREPORTNAME

pdvParamDiscreteValue.Value = FIELDNAME.tostring
pvParamValue.Add(pdvParamDiscreteValue)
crDoc.DataDefinition.ParameterFields("@P_PARAMETERNAME").ApplyCurrentValues(pvParamValue)

Try this...........



Private Sub btn_save_print_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_save_print.Click

Dim obj As New Letter_print


obj.Code=txt_code.text
obj.doc_nm = txt_doc_name.Text
obj.address = txt_address.Text

obj.ShowDialog(Me)

End Sub

Public Class _Print
Public CodeAs String = ""
Public doc_nm As String = ""
Public address As String = ""


Private Sub Letter_Print_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim k As New Letter_report

k.SetParameterValue("code1,code

k.SetParameterValue("doc_nm1", doc_nm)
k.SetParameterValue("address1", address)


CrystalReportViewer1.ReportSource = k

End Sub
End Class

CrystalReportViewer1.Refresh()
     Dim rpt As New ReportDocument
     rpt.FileName = "c:\Users\sandy\BCA\CBT\result2.rpt"
     Dim paramDV As New ParameterDiscreteValue()
     paramDV.Value = LoginForm.UsernameTextBox.Text
     rpt.Refresh()
     Dim paramfields As ParameterFields = Me.CrystalReportViewer1.ParameterFieldInfo
     Dim param As New ParameterField
     Dim params As New ParameterFields
     param.Name = "result"
     Dim param_value As New ParameterDiscreteValue
     param_value.Value = LoginForm.UsernameTextBox.Text
     param.CurrentValues.Clear()
     param.CurrentValues.Add(param_value)
     params.Add(param)
     CrystalReportViewer1.ParameterFieldInfo = params
     rpt.Refresh()
     CrystalReportViewer1.ReportSource = rpt
     CrystalReportViewer1.ReuseParameterValuesOnRefresh = True