DispatcherTimer等待循环

Question

我想每隔几秒加载一张图片.我创建DispatcherTimer,我想在计时器滴答无所事事,只是等待间隔.我怎样才能做到这一点？

if (window.DialogResult == true) {
                st=window.st;
                for(int i=0;i<=st;i++){
                    timer = new DispatcherTimer();
                    timer.Interval = new TimeSpan(0,0,5);
                    timer.Tick += new EventHandler(timer_Tick);
                    timer.Start();
                arr[i]=window.arr[i];
                image1.Source = arr[i];
                }
            }

在这里,我现在空了.

void timer_Tick(object sender, EventArgs e)
        {

        }

Answer 1

一种选择是使用async/ await:

async void button_click(object sender, RoutedEventArgs e)
{
    // prepare the array
    // ...

    for (var i = 0; i < 100; i++)
    {
        image1.Source = arr[i];
        await Task.Delay(5000);
    }
}

您可能希望确保button_click在异步循环仍在迭代时不会重新进入.检查Lucian Wishick的"Async re-entrancy,以及处理它的模式".

如果你坚持使用DispatcherTimer:

async void button_click(object sender, RoutedEventArgs e)
{
    // prepare the array
    // ...

    var tcs = new TaskCompletionSource<object>();
    var timer = new DispatcherTimer();
    timer.Interval = new TimeSpan(0,0,5);
    timer.Tick += (_, __) => tcs.SetResult(Type.Missing);
    timer.Start();
    try
    {
        for (var i = 0; i < 100; i++)
        {
            image1.Source = arr[i];
            await tcs.Task;
            tcs = new TaskCompletionSource<object>();
        }
    }
    finally
    {
        timer.Stop();
    }
}