UI延遲 - Dispatcher Queue

Dispatcher Queue

WPF消息處理隊列，會根據優先級進行一一處理。

獲取Dispatcher Queue的長度

     var queueLength = 0;
     Dispatcher.Hooks.OperationPosted += (o, e) => Interlocked.Increment(ref queueLength);
     Dispatcher.Hooks.OperationStarted += (o, e) => Interlocked.Decrement(ref queueLength);
     Dispatcher.Hooks.OperationAborted += (o, e) => Interlocked.Decrement(ref queueLength);

MSDN中關於DispatcherHook的定義

對於Dispatcher隊列的進行的任務可進地監控上面這些任務的方式進行查看，添加到Dispatcher Queue中的任務是一個個DispatcherOperation, 其有一個Name屬性，可用來獲取是否是自行添加到Dispatcher Queue中的任務，打印出結果諸如這樣的形式：

2016/05/11 11:48:00//End] Priority: Background Name: UIH.Mcsf.PA.UtilityCSharp.Commons.CustomCollectionView`1+<>c__DisplayClass4[UIH.Mcsf.PA.UtilityCSharp.Models.StudyInfoModel].<OnInternalListCountChanged>b__0

這可以用來查看Dispatcher Queue的性能問題。

反射獲取Name
PropertyInfo pro = typeof(DispatcherOperation).GetProperty("Name", BindingFlags.Instance | BindingFlags.GetProperty | BindingFlags.NonPublic);

查看性能問題的示例代碼：

        Dispatcher.Hooks.OperationPosted += new DispatcherHookEventHandler(Hooks_OperationPosted);
        Dispatcher.Hooks.OperationCompleted += new DispatcherHookEventHandler(Hooks_OperationCompleted);
        void Hooks_OperationCompleted(object sender, DispatcherHookEventArgs e)
        {
            var name = pro.GetValue(e.Operation, null);
            var str = string.Format("End] Priority: {0} Name: {1} Time:{2}", e.Operation.Priority, name, DateTime.Now);
            FileOp.WTF(str);
        }

        void Hooks_OperationPosted(object sender, DispatcherHookEventArgs e)
        {
            var name = pro.GetValue(e.Operation, null);
            var str = string.Format("Start] Priority: {0} Name: {1} Time:{2}", e.Operation.Priority, name, DateTime.Now);
            FileOp.WTF(str);
        }