WPF Windows occupy full screen

AllowsTransparency="True"
WindowStyle="None"
KeyDown="Window_KeyDown"

public MainWindow()
{
    InitializeComponent();
    this.SizeChanged += MainWindow_SizeChanged;
}

private void MainWindow_SizeChanged(object sender, SizeChangedEventArgs e)
{
    this.Width = SystemParameters.PrimaryScreenWidth;
    this.Height = SystemParameters.PrimaryScreenHeight;
}