Dependency property changed example

public double ScaleFactor

{

    get { return (double)GetValue(ScaleFactorProperty); }

    set { SetValue(ScaleFactorProperty, value); }

}



// Using a DependencyProperty as the backing store for ScaleFactor.  This enables animation, styling, binding, etc...

public static readonly DependencyProperty ScaleFactorProperty =

    DependencyProperty.Register("ScaleFactor", typeof(double), typeof(ToolBlockControl), 
        new UIPropertyMetadata(1.0,new PropertyChangedCallback(ScaleFactorChangedCallBack)));





private static void ScaleFactorChangedCallBack(DependencyObject obj, DependencyPropertyChangedEventArgs args)

{

    var toolBlockControl = obj as ToolBlockControl;

    double scaleFactor = (double)args.NewValue;

    toolBlockControl.Width = toolBlockControl.mActualWidth * scaleFactor;

    toolBlockControl.Height = toolBlockControl.mActualHeight * scaleFactor;

}