Question

我的窗户上有按钮。在用户点击按钮后，我希望我的应用程序为加载标签设置动画（带有旋转），在另一个线程中从数据库中获取一些数据。 从数据库动画加载数据后必须结束。任务看似简单，但不起作用。问题在于动画无论我做什么动画，只有在不需要时从数据库加载后才会启动。

请帮助。这里有一些代码：

private void LoginButtonClick(object sender, RoutedEventArgs e)
{ 
  Thread thread = new Thread(new ThreadStart(
    delegate()
    {
      DispatcherOperation dispatcherOp =
        this.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(
          delegate()
          {
            var da = new DoubleAnimation(360, 0, new Duration(TimeSpan.FromSeconds(1)));
            var rt = new RotateTransform();
            loadingLabel.RenderTransform = rt;
            loadingLabel.RenderTransformOrigin = new Point(0.5, 0.5);
            da.RepeatBehavior = RepeatBehavior.Forever;
            rt.BeginAnimation(RotateTransform.AngleProperty, da);
          }));
      dispatcherOp.Completed += new EventHandler(DispatcherOpCompleted);
    }));
  thread.Start();
}

void DispatcherOpCompleted(object sender, EventArgs e)
{
  //Loading From Database
}

Answer 1

Dispatcher.Completed事件在主UI线程上执行。您的工作线程只是将调度程序操作排队并退出。而不是创建一个启动动画然后在Completed处理程序中加载数据库的线程，只需在主线程中启动动画，然后创建一个工作线程来进行数据库加载。

private void LoginButtonClick(object sender, RoutedEventArgs e)
{
  var da = new DoubleAnimation(360, 0, new Duration(TimeSpan.FromSeconds(1)));
  var rt = new RotateTransform();
  loadingLabel.RenderTransform = rt;
  loadingLabel.RenderTransformOrigin = new Point(0.5, 0.5);
  da.RepeatBehavior = RepeatBehavior.Forever;
  rt.BeginAnimation(RotateTransform.AngleProperty, da);

  Thread thread = new Thread(new ThreadStart(LoadData));
  thread.Start();
}

void LoadData()
{
  //Loading From Database

  // Use a Dispatch.BeginInvoke here to stop the animation
  // and do any other UI updates that use the results of the database load
}

WPF C＃中的动画加载

1 个答案: