我在Stack Overflow上找到了几个问题以及几篇博客文章,它们都涉及到这个主题,但不幸的是,它们都不能满足我的需求。我将从一些示例代码开始展示我想要完成的内容。
using System;
using System.Security.Permissions;
using System.Threading.Tasks;
using System.Windows.Threading;
using Microsoft.VisualStudio.TestTools.UnitTesting;
namespace MyApp
{
[TestClass]
public class MyTests
{
private int _value;
[TestMethod]
public async Task TimerTest()
{
_value = 0;
var timer = new DispatcherTimer {Interval = TimeSpan.FromMilliseconds(10)};
timer.Tick += IncrementValue;
timer.Start();
await Task.Delay(15);
DispatcherUtils.DoEvents();
Assert.AreNotEqual(0, _value);
}
private void IncrementValue(object sender, EventArgs e)
{
_value++;
}
}
internal class DispatcherUtils
{
[SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
public static void DoEvents()
{
var frame = new DispatcherFrame();
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, new DispatcherOperationCallback(ExitFrame), frame);
Dispatcher.PushFrame(frame);
}
private static object ExitFrame(object frame)
{
((DispatcherFrame)frame).Continue = false;
return null;
}
}
}
如果我使用一个普通的计时器而不是DispatcherTimer,那么这段代码可以正常工作。但是DispatcherTimer从未触发。我错过了什么?我需要做什么才能让它触发?