private void SignIn_Click(object sender, RoutedEventArgs e)
{
MainAppMenu mainAppMenu = DependencyInjectorBLL.Resolve <MainAppMenu>();
mainAppMenu.Show();
this.Close();
}
protected override void OnStartup(StartupEventArgs e)
{
MainAppMenu mainWindow = DependencyInjectorBLL.Resolve <MainAppMenu>();
mainWindow.Show();
}