private void BtnCalcTotal_Click(object sender, RoutedEventArgs e)
{
vm.CalculateTotalCharge();
//open DetailWindow
if (dw == null)
{
dw = new DetailWindow(vm)
{
Owner = this,
WindowStartupLocation = WindowStartupLocation.CenterOwner
};
dw.Closed += DW_Closed;
dw.Show();
}
}
private void DW_Closed(object sender, System.EventArgs e) => dw = null;