private void Btread_Click(object sender, RoutedEventArgs e)
        {
            System.Windows.Forms.OpenFileDialog dlgOpen = new
            System.Windows.Forms.OpenFileDialog();



            if (dlgOpen.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                StreamReader sr = new StreamReader(dlgOpen.FileName, false);
                tbtext = sr.ReadToEnd();
            }
        }