How To Save Data From DatagridView To Sql Server 2008 In Vb.NEt

Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
       Dim comd As SqlCommand = con.CreateCommand()
       If txtPONumber.Text <> " " Then
           Try
               con.ConnectionString = obj.getconnectionstring
               con.Open()
               comd.Connection = con
               comd.CommandText = "Insert into PurchaseOrder(PoNumber,PoDate,PoCompanyName,PoSiteName,PoContactNumber,ItemNumber,itemName,Quantity,Rate,TotalAmount,GrossAmount,Discount,tax,FinalAmount) values('" & txtPONumber.Text & "','" & lblDatetime.Text & "','" & cbxCompanyName.Text & "','" & txtSiteName.Text & "','" & txtContact.Text & "',@ItemNum,@ItemNam,@Qty,@Rte,@TotalAmt,'" & txtGrossAmount.Text & "','" & txtDiscount.Text & "','" & txtTax.Text & "','" & txtFinalAmount.Text & "')"

               'Adding Parameters
               comd.Parameters.Add("@ItemNum", SqlDbType.VarChar, 50)
               comd.Parameters.Add("@ItemNam", SqlDbType.VarChar, 50)
               comd.Parameters.Add("@Qty", SqlDbType.VarChar, 50)
               comd.Parameters.Add("@Rte", SqlDbType.VarChar, 50)
               comd.Parameters.Add("@TotalAmt", SqlDbType.VarChar, 50)

               comd.Prepare()
               'Data Inserted

               For Each row As DataGridViewRow In DGVPO.Rows
                   If Not row.IsNewRow Then
                       comd.Parameters("@ItemNum").Value = row.Cells(0).Value.ToString
                       comd.Parameters("@ItemNam").Value = row.Cells(1).ToString
                       comd.Parameters("@Qty").Value = row.Cells(2).ToString
                       comd.Parameters("@Rte").Value = row.Cells(3).ToString
                       comd.Parameters("@TotalAmt").Value = row.Cells(4).ToString
                   End If
               Next
               comd.ExecuteNonQuery()
               MessageBox.Show("Data Inserted")
           Catch ex As Exception
               MessageBox.Show("Error :" & ex.ToString())
           Finally
               con.Close()
           End Try
       Else
           MessageBox.Show("Enter PoNumber")
       End If

   End Sub