private void NewFile(object sender, RoutedEventArgs e)
 {
     if (MessageBox.Show("Would you like to save ?", "Warning", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
     {
         var dialog = new Microsoft.Win32.SaveFileDialog();
         dialog.Filter   = "Text File(*txt)|*.txt|Allfile(*.*)|*.*";
         dialog.FileName = "File.txt";
         if (dialog.ShowDialog() == true)
         {
             using (var stream = dialog.OpenFile())
             {
                 var range = new TextRange(RTBeditor.Document.ContentStart, RTBeditor.Document.ContentEnd);
                 range.Save(stream, DataFormats.Text);
             }
         }
     }
     else
     {
         RTBeditor.SelectAll();
         RTBeditor.Selection.Text = "";
     }
 }
 private void Button_Click(object sender, RoutedEventArgs e)
 {
     RTBeditor.SelectAll();
     RTBeditor.Selection.Text = "";
 }
 private void Paste(object sender, RoutedEventArgs e)
 {
     RTBeditor.Paste();
 }
 private void Copy(object sender, RoutedEventArgs e)
 {
     RTBeditor.Copy();
 }
 private void Redo(object sender, RoutedEventArgs e)
 {
     RTBeditor.Redo();
 }