การ Add ข้อมูลลง DataTable ครับ ปัญหาอยู่ด้านในครับ มีตัวอย่างที่เคยทำครับ

Private Sub LoadGridViewSizeData()
            If IsNothing(Session("SizeTable")) Then
                dt = New DataTable()
                dt.Columns.Add(New DataColumn("TopWidth", GetType(String)))
                dt.Columns.Add(New DataColumn("MidWidth", GetType(String)))
                dt.Columns.Add(New DataColumn("BottomWidth", GetType(String)))
                dt.Columns.Add(New DataColumn("WidthAVG", GetType(String)))
                dt.Columns.Add(New DataColumn("LeftLength", GetType(String)))
                dt.Columns.Add(New DataColumn("RigthLength", GetType(String)))
                dt.Columns.Add(New DataColumn("LengthAVG", GetType(String)))
                dt.Columns.Add(New DataColumn("SizeNote", GetType(String)))
                Session("SizeTable") = dt
            End If

            dt = DirectCast(Session("SizeTable"), DataTable)
            gvS_LoadSize.DataSource = dt
            gvS_LoadSize.DataBind()
End Sub

Private Sub AddToTable()
                Dim dr As DataRow = dt.NewRow

                dr("TopWidth") = txtPK_WidthTop.Text.Trim
                dr("MidWidth") = txtPK_WidthMid.Text.Trim
                dr("BottomWidth") = txtPK_WidthBottom.Text.Trim
                dr("WidthAVG") = ((CType(txtPK_WidthTop.Text.Trim, Decimal) + CType(txtPK_WidthMid.Text.Trim, Decimal) + CType(txtPK_WidthBottom.Text.Trim, Decimal)) / 3).ToString("n2")
                dr("LeftLength") = txtPK_LengthLeft.Text.Trim
                dr("RigthLength") = txtPK_LengthRigth.Text.Trim
                dr("LengthAVG") = ((CType(txtPK_LengthLeft.Text.Trim, Decimal) + CType(txtPK_LengthRigth.Text.Trim, Decimal)) / 2).ToString("n2")
                dr("SizeNote") = txtPK_SizeNote.Text.Trim

                dt.Rows.Add(dr)
                Session("SizeTable") = dt
                LoadGridViewSizeData()
                Reset()
                txtPK_WidthTop.Focus()
End Sub

Private Sub AddToDB()
                 iMAX = IIf(Count <= 0, 1, Count + 1)
                    If iMAX < 1000 Then
                        Session("PKID") = "PK" & CStr(Format(Now.Date.ToString("yyyyMMdd", New CultureInfo("en-US")))) & iMAX.ToString("000")
                        dt = DirectCast(Session("SizeTable"), DataTable)
                        For i = 0 To dt.Rows.Count - 1

                            strSQL = "INSERT INTO Size (PK_ID,S_WIDTHTOP,S_WIDTHMID,S_WIDTHBOTTOM,S_LENGTHLEFT,S_LENGTHRIGTH,S_NOTE) VALUES ('" & Session("PKID").ToString() & "','" & dt.Rows(i)("TopWidth") & "','" & dt.Rows(i)("MidWidth") & "','" & dt.Rows(i)("BottomWidth") & "','" & dt.Rows(i)("LeftLength") & "','" & dt.Rows(i)("RigthLength") & "','" & dt.Rows(i)("SizeNote") & "')"
                            objCmd = New SqlCommand(strSQL, objConn)

                            With objCmd
                                .Connection = objConn
                                .CommandText = strSQL
                                .CommandType = CommandType.Text
                                .ExecuteNonQuery()
                            End With
                        Next

                        objConn.Close()
                        objConn = Nothing
                        MsgBox("บันทึกข้อมูลสำเร็จ")
                     End If
End Sub