WPF事件触发鼠标停止移动后， [英] WPF event that triggers after the mouse stops moving

问题描述

我写一个WPF应用程序。 我想触发一个事件一旦鼠标停止移动。

这是我如何试图做到这一点。我创建了一个定时器，倒计时5秒。此计时器重置，每次鼠标移动。 这种想法是，当下的鼠标停止移动，定时器停止被重置，并倒数5到零，然后调用Tick事件处理程序，它会显示一个消息框。

那么，它并不会达到预期效果，而且洪水给我警报消息。我究竟做错了什么？

  DispatcherTimer定时器;

私人无效Window_MouseMove（对象发件人，发送MouseEventArgs E）
{
    定时器=新DispatcherTimer（）;
    timer.Interval =新时间跨度（0,0，5）;
    timer.Tick + =新的EventHandler（timer_Tick）;
    timer.Start（）;
}

无效timer_Tick（对象发件人，EventArgs的）
{
    的MessageBox.show（鼠标停止移动）;
}
 

解决方案

您需要解开的事件前再次钩住这样的 -

 私人无效poc_MouseMove（对象发件人，发送MouseEventArgs E）
{
   如果（定时器！= NULL）
   {
      timer.Tick- = timer_Tick;
   }
   定时器=新DispatcherTimer（）;
   timer.Interval =新时间跨度（0,0，5）;
   timer.Tick + =新的EventHandler（timer_Tick）;
   timer.Start（）;
}
 

说明

每当鼠标移动时，将创建DispatcherTimer的新实例，并挂钩Tick事件而不用担心会有脱钩的事件previous实例什么，你做的是。因此，你看到洪水淹没的消息后，计时器停止所有实例。

此外，你应该解开它，否则previous实例不会被垃圾回收，因为他们仍然坚决引用。

I am writing a WPF application. I want to trigger an event once the mouse stops moving.

This is how I tried to do it. I created a timer which counts down to 5 seconds. This timer is "reset" every time the mouse moves. This idea is that the moment the mouse stops moving, the timer stops being reset, and counts down from 5 to zero, and then calls the tick event handler, which displays a message box.

Well, it doesn't work as expected, and it floods me with alert messages. What am I doing wrong?

DispatcherTimer timer;

private void Window_MouseMove(object sender, MouseEventArgs e)
{
    timer = new DispatcherTimer();
    timer.Interval = new TimeSpan(0, 0, 5);
    timer.Tick += new EventHandler(timer_Tick);
    timer.Start();
}

void timer_Tick(object sender, EventArgs e)
{
    MessageBox.Show("Mouse stopped moving");
}

解决方案

You need to unhook the event before hooking it again like this -

private void poc_MouseMove(object sender, MouseEventArgs e)
{
   if (timer != null)
   {
      timer.Tick-= timer_Tick;
   }
   timer = new DispatcherTimer();
   timer.Interval = new TimeSpan(0, 0, 5);
   timer.Tick += new EventHandler(timer_Tick);
   timer.Start();
}

Explanation

What you doing is whenever a mouse moves, you create a new instance of DispatcherTimer and hook Tick event to it without unhooking the event for previous instance. Hence, you see flooded messages once timer stops for all the instances.

Also, you should unhook it otherwise previous instance won't be garbage collected since they are still strongly referenced.

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