DataGridView to datatable 並欄位作過濾重複資料

DataGridView to datatable 並欄位作過濾重複資料
 Dim tmp_note As String = ""
 If DGridV.RowCount > 0 Then
    Dim dt As New DataTable()
    dt = TryCast(DGridV.DataSource, DataTable)
    Dim tmpTable As DataTable = dt.DefaultView.ToTable("tmpTable", True, "temp")
    For i As Integer = 0 To tmpTable.Rows.Count - 1                   
        MessageBox.Show(tmpTable.Rows(i).Item("temp").ToString())
    Next
End If