สอบถามแสดงค่าข้อมูลลง DataGridView โดยใช้ความสัมพันธ์ของข้อมูล ของ VB.Net ค่ะ

Public Class Form4
    Dim cnn As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\PostCode.mdb;Persist Security Info=True;Jet OLEDB:Database Password=4410210091"
    Private Sub Form4_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        DataGridView1.DataSource = GetTableOLEDB("SELECT * FROM Sett_Post_Province", cnn)
        DataGridView2.DataSource = GetTableOLEDB("SELECT * FROM Sett_Post_PostCode", cnn)
    End Sub
    Private Function GetTableOLEDB(SQL As String, strConn As String) As Data.DataTable
        Dim conn As New Data.OleDb.OleDbConnection(strConn)
        Dim ds As New System.Data.DataSet()
        conn.Open()
        Dim strQuery As String = SQL
        Dim adapter As New Data.OleDb.OleDbDataAdapter(strQuery, conn)
        adapter.Fill(ds)
        Return ds.Tables(0)
    End Function

    Private Sub DataGridView1_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick

    End Sub

    Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
        DataGridView2.DataSource = GetTableOLEDB("SELECT * FROM Sett_Post_PostCode where Pnv =" & DataGridView1(0, e.RowIndex).Value, cnn)
    End Sub
End Class

Private Function GetTableOLEDB(SQL As String, strConn As String) As Data.DataTable
        Dim conn As New Data.OleDb.OleDbConnection(strConn)
        Dim ds As New System.Data.DataSet()
        conn.Open()
        Dim strQuery As String = SQL
        Dim adapter As New Data.OleDb.OleDbDataAdapter(strQuery, conn)
        adapter.Fill(ds)
        Return ds.Tables(0)
    End Function