WPF UserControl销毁前处理

若需要在销毁UserControl前执行操作，不能指望使用Unloaded方法，你需要在UserControl的构造函数中增加类似如下代码：

public UCCaptureQuery()
{
     InitializeComponent();
     Dispatcher.ShutdownStarted += (object sender, EventArgs e)=>
     {
         _stopThread = true;
         if (null != _threadReadStatus)
         {
             _threadReadStatus.Join();
             _threadReadStatus = null;
         }
     };
 }

转自http://geekswithblogs.net/cskardon/archive/2008/06/23/dispose-of-a-wpf-usercontrol-ish.aspx