Question

我有一个窗口，显示另一个线程正在运行时的“工作”动画。窗口显示，我可以看到进度条，但动画被冻结。代码在ViewModel上运行，调度程序在构造函数中创建：

_dispatcher = Dispatcher.CurrentDispatcher;

创建动画并运行流程的代码如下：

Working wrk;    
protected void Search()
{
  ImplementSearch();

  wrk = new Working();
  wrk.Owner = (MainWindow)App.Current.MainWindow;
  wrk.WindowStartupLocation = WindowStartupLocation.CenterOwner;
  wrk.HeadingMessage = "Searching...";
  wrk.UpdateMessage = "Running your search";
  wrk.ShowDialog();      
}

void ImplementSearch()
{
  System.Threading.Thread thread = new System.Threading.Thread(
    new System.Threading.ThreadStart(
      delegate()
      {
        System.Windows.Threading.DispatcherOperation
          dispatcherOp = _dispatcher.BeginInvoke(
          System.Windows.Threading.DispatcherPriority.Normal,
          new Action(
            delegate()
            {                  
              ResetSearch();

              string ret = _searchlogic.PerformSearch(SearchTerm, ref _matchingobjects, TypeOfFilter());
              if (ret != null)
                SearchMessage = ret;

              if (_matchingobjects.Count > 0)
              {
                DataRow row;
                foreach (SearchLogicMatchingObjects item in _matchingobjects)
                {
                  row = _dt.NewRow();
                  row["table"] = item.Table;
                  row["pk"] = item.PK;
                  _dt.Rows.Add(row);
                }

                SelectCurrent();
              }          
            }
        ));

        dispatcherOp.Completed += new EventHandler(dispatcherOp_Completed);
      }
  ));

  thread.Start();
}

void dispatcherOp_Completed(object sender, EventArgs e)
{
  wrk.Close();
}

我无法弄清楚动画停止的原因？有人可以帮忙吗？感谢

Answer 1

我认为你想在后台线程上做实际工作，而不是将所有东西编组到UI线程，这就是BeginInvoke所做的！通过使用BeginInvoke在UI线程上执行所有操作，您的动画将无法运行。

Working wrk;     
protected void Search() 
{ 
  ImplementSearch(); 

  wrk = new Working(); 
  wrk.Owner = (MainWindow)App.Current.MainWindow; 
  wrk.WindowStartupLocation = WindowStartupLocation.CenterOwner; 
  wrk.HeadingMessage = "Searching..."; 
  wrk.UpdateMessage = "Running your search"; 
  wrk.ShowDialog();       
} 

void ImplementSearch() 
{ 
    Thread thread = new Thread(new ThreadStart( 
      delegate() 
      { 
          // Call to function which changes UI - marshal to UI thread.
          _dispatcher.BeginInvoke((Action)(() => ResetSearch()));

          string ret = _searchlogic.PerformSearch(SearchTerm, ref _matchingobjects, TypeOfFilter()); 

          if (ret != null) 
          {
              // Call to function which changes UI - marshal to UI thread.
              _dispatcher.BeginInvoke((Action<string>)((r) => SearchMessage = r), ret);
          }

          if (_matchingobjects.Count > 0) 
          { 
            DataRow row; 
            foreach (SearchLogicMatchingObjects item in _matchingobjects) 
            { 
              row = _dt.NewRow(); 
              row["table"] = item.Table; 
              row["pk"] = item.PK; 
              _dt.Rows.Add(row); 
            }  

            // Call to function which changes UI - marshal to UI thread.
            _dispatcher.BeginInvoke((Action)(() => SelectCurrent()));
          }           
        } 

        wrk.Close();
  })); 
  thread.Start();
}

Answer 2

您的线程没有任何用处 - 通过使用_dispatcher.BeginInvoke来运行搜索，您实际上是在UI线程上执行搜索，这会阻止您的动画。仅将后台线程中的调度程序用于操作UI控件或导致触发PropertyChanged事件的操作。

当另一个线程运行时，WPF动画停止

2 个答案: