Silverlight dependency property属性的定义

具体如下：
public static readonly DependencyProperty IsSpinningProperty =
    DependencyProperty.Register(
    "IsSpinning", typeof(Boolean),
    typeof(SilverlightExampleClass), null
    );
public bool IsSpinning
{
    get { return (bool)GetValue(IsSpinningProperty); }
    set { SetValue(IsSpinningProperty, value); }
}
 引用http://msdn.microsoft.com/en-us/library/cc221408