public MainWindow()
{
InitializeComponent();
ModalDialog.SetParent(this.DrawingCanvas);
drawArea = new DrawingArea(this.DrawingCanvas);
drawArea.Tool = CurrentTool.Pencil;
drawArea.StrokeColor = new SolidColorBrush(Colors.YellowGreen);
drawArea.FillColor = new SolidColorBrush(Colors.White);
drawArea.StrokeWidth = 5;
this.DataContext = drawArea;
}