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