如何取消HttpClient GET Web请求

Question

是否可以取消HttpClient GET web request in Windows 8.我正在寻找一个解决方案来取消我的网页请求,如果用户从页面按回键.在我的应用程序中,我使用的static class是创建Web请求.

Alos我正在使用MVVM Light,并static viewmodels在应用程序内.

在当前情况下,即使用户按下后退按钮,vm保持活动和回叫也会到达并执行VM.

所以我正在寻找一个解决方案来取消背面的请求.

Answer 1

试试这个

protected async override void OnNavigatedTo(NavigationEventArgs e)
{
    await HttpGetRequest();
}

public CancellationTokenSource cts = new CancellationTokenSource();
private async Task HttpGetRequest()
{
    try
    {
        DateTime now = DateTime.Now;
        var httpClient = new HttpClient();
        var message = new HttpRequestMessage(HttpMethod.Get, "https://itunes.apple.com/us/rss/toppaidapplications/limit=400/genre=6000/json");
        var response = await httpClient.SendAsync(message, cts.Token);
        System.Diagnostics.Debug.WriteLine("HTTP Get request completed. Time taken : " + (DateTime.Now - now).TotalSeconds + " seconds.");
    }
    catch (TaskCanceledException)
    {
        System.Diagnostics.Debug.WriteLine("HTTP Get request canceled.");
    }
}

private void btnCancel_Click(object sender, RoutedEventArgs e)
{
    cts.Cancel();
}