/// <summary>
/// method : newToolStripMenuItem_Click
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
calculation.Clear();
dlgSave.FileName = String.Empty;
}
private void Clear_Click(object sender, RoutedEventArgs e)
{
diplayWindow.Text = cal.Clear();
}
private void ButtonClear_Click(object sender, EventArgs e)
{
calculation.Clear();
}