ขอสอบถามโค้ด vb.NET combobox เลือก จังหวัด อำเภอ ตำบล ทำยังไงมันก็ไม่ขึ้น ช่วยดูดค้ดให้หน่อยครับ

    Private Sub frmOrganization_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Dim sqlorganization As String = ""

        sqlorganization = " select * from organization"
        sqlorganization &= " ORDER BY ORGID"

        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With
      
      
   Dim sqlprovince_th As String = ""
        sqlprovince_th = "SELECT * FROM province ORDER BY PROVINCEID"
        da = New SqlDataAdapter(sqlprovince_th, Conn)
        da.Fill(ds, "province")


        With cboPROVINCE_TH
            .DisplayMember = "PROVINCE_TH"
            .ValueMember = "PROVINCEID"
            .DataSource = ds.Tables("province")
            .DataBindings.Add("SelectedValue", ds, "organization.PROVINCEID")
        End With



    End Sub


    Private Sub cboDISTRICT_TH_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboDISTRICT_TH.SelectedIndexChanged


        Dim sqldistric As String = ""
        sqldistric = " select * from district"

        sqldistric &= " where PROVINCEID='" & cboPROVINCE_TH.SelectedIndex & "'"

        da = New SqlDataAdapter(sqldistric, Conn)
        da.Fill(ds, "district")


        With cboDISTRICT_TH
            .DisplayMember = "DISTRICT_TH"
            .ValueMember = "PROVINCEID"
            .DataSource = ds.Tables("district")
            .DataBindings.Add("SelectedValue", ds, "district.PROVINCEID")
        End With


    End Sub