ขอวิธีสั่งพิมพ์บาร์โค้ด EAN13 แปลงจากบาร์โค้ดเป็น String เพื่อเตรียมปริ้นบาร์โค้ดนะครับ

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim CodeClair As String = "001034360548"
        CodeClair = CodeClair.PadRight(12, "0"c)
        MsgBox(EAN13(CodeClair))
    End Sub

Public Function EAN13(ByVal chaine As String) As String
        Dim i As Integer
        Dim first As Integer
        Dim checksum As Integer = 0
        Dim CodeBarre As String = ""
        Dim tableA As Boolean

        If Regex.IsMatch(chaine, "^\d{12}$") Then
            For i = 1 To 11 Step 2
                System.Diagnostics.Debug.WriteLine(chaine.Substring(i, 1))
                checksum += Convert.ToInt32(chaine.Substring(i, 1))
            Next
            checksum *= 3
            For i = 0 To 11 Step 2
                checksum += Convert.ToInt32(chaine.Substring(i, 1))
            Next

            chaine += (10 - checksum Mod 10) Mod 10

            CodeBarre = chaine.Substring(0, 1) & ChrW(65 + Convert.ToInt32(chaine.Substring(1, 1)))
            first = Convert.ToInt32(chaine.Substring(0, 1))
            For i = 2 To 6
                tableA = False
                Select Case i
                    Case 2
                        If first >= 0 AndAlso first <= 3 Then
                            tableA = True
                        End If
                        Exit Select
                    Case 3
                        If first = 0 OrElse first = 4 OrElse first = 7 OrElse first = 8 Then
                            tableA = True
                        End If
                        Exit Select
                    Case 4
                        If first = 0 OrElse first = 1 OrElse first = 4 OrElse first = 5 OrElse first = 9 Then
                            tableA = True
                        End If
                        Exit Select
                    Case 5
                        If first = 0 OrElse first = 2 OrElse first = 5 OrElse first = 6 OrElse first = 7 Then
                            tableA = True
                        End If
                        Exit Select
                    Case 6
                        If first = 0 OrElse first = 3 OrElse first = 6 OrElse first = 8 OrElse first = 9 Then
                            tableA = True
                        End If
                        Exit Select
                End Select

                If tableA Then
                    CodeBarre += ChrW(65 + Convert.ToInt32(chaine.Substring(i, 1)))
                Else
                    CodeBarre += ChrW(75 + Convert.ToInt32(chaine.Substring(i, 1)))
                End If
            Next
            CodeBarre += "*"
            'Ajout s้parateur central / Add middle separator
            For i = 7 To 12
                CodeBarre += ChrW(97 + Convert.ToInt32(chaine.Substring(i, 1)))   <<<<< Error บันทัดนี้นะครับ
            Next
            CodeBarre += "+"
        End If
        Return CodeBarre
    End Function

  Public Function EAN13(ByVal chaine As String) As String
        Dim i As Integer
        Dim first As Integer
        Dim checksum As Integer = 0
        Dim CodeBarre As String = ""
        Dim tableA As Boolean


        If Microsoft.VisualBasic.Len(chaine) = 12 Then
            If Convert.ToInt64(chaine) >= 100000000000 Then
                For i = 1 To 11 Step 2
                    System.Diagnostics.Debug.WriteLine(chaine.Substring(i, 1))
                    checksum += Convert.ToInt32(chaine.Substring(i, 1))
                Next
                checksum *= 3
                For i = 0 To 11 Step 2
                    checksum += Convert.ToInt32(chaine.Substring(i, 1))
                Next

                chaine = chaine & (10 - checksum Mod 10) Mod 10

                CodeBarre = chaine.Substring(0, 1) & ChrW(65 + Convert.ToInt32(chaine.Substring(1, 1)))
                first = Convert.ToInt32(chaine.Substring(0, 1))
                For i = 2 To 6
                    tableA = False
                    Select Case i
                        Case 2
                            If first >= 0 AndAlso first <= 3 Then
                                tableA = True
                            End If
                            Exit Select
                        Case 3
                            If first = 0 OrElse first = 4 OrElse first = 7 OrElse first = 8 Then
                                tableA = True
                            End If
                            Exit Select
                        Case 4
                            If first = 0 OrElse first = 1 OrElse first = 4 OrElse first = 5 OrElse first = 9 Then
                                tableA = True
                            End If
                            Exit Select
                        Case 5
                            If first = 0 OrElse first = 2 OrElse first = 5 OrElse first = 6 OrElse first = 7 Then
                                tableA = True
                            End If
                            Exit Select
                        Case 6
                            If first = 0 OrElse first = 3 OrElse first = 6 OrElse first = 8 OrElse first = 9 Then
                                tableA = True
                            End If
                            Exit Select
                    End Select
                    MsgBox(Convert.ToInt32(chaine.Substring(i, 1)))
                    If tableA Then
                        CodeBarre += ChrW(65 + Convert.ToInt32(chaine.Substring(i, 1)))
                    Else
                        CodeBarre += ChrW(75 + Convert.ToInt32(chaine.Substring(i, 1)))
                    End If
                Next
                CodeBarre += "*"

                For i = 7 To 12

                    CodeBarre += ChrW(97 + Convert.ToInt32(chaine.Substring(i, 1)))
                Next
                CodeBarre += "+"
            End If
        End If
        Return CodeBarre
    End Function