Now,I have already fix it by improve that code to this:
sqlcmd = "select * from tb_employee"
cmd = New OleDbCommand(sqlcmd, cn)
dr = cmd.ExecuteReader()
dt.Load(dr)
datasetReport.Tables(0).Load(dr)
dr.Close()
cn.Close()
rds.Name = "dsReportGroupByProject_dtReport"
rds.Value = dt
gvtest.DataSource = datasetReport.Tables(0)
ReportViewer1.LocalReport.DataSources.Clear()
Me.ReportViewer1.LocalReport.DataSources.Add(rds)
Dim rpt(2) As ReportParameter
rpt(0) = New ReportParameter("monthStart", ddlmonth.SelectedItem.ToString)
rpt(1) = New ReportParameter("monthStop", ddlmonth.SelectedItem.ToString)
rpt(2) = New ReportParameter("year", ddlyear.SelectedItem.ToString)
Me.ReportViewer1.LocalReport.SetParameters(rpt)
Me.ReportViewer1.RefreshReport()
Thank you for myself and my effort.