web-services - WP8 SDK import Service Reference with task-based operations not possible

Question

到目前为止，在 VS2012 中使用“生成基于任务的操作”导入服务引用似乎不起作用。它是灰色的。

针对 WPF 的新项目进行的测试工作正常 - 我可以选择基于任务的操作或异步操作。

有没有一种简单的方法可以将异步调用包装在任务中？

Answer 1

Is there a simple way on wrapping the async call in a task?

WebClient.DownloadStringCompleted 示例

public static class WebClientAsyncExtensions
{
    public static Task<string> DownloadStringTask(this WebClient client, Uri address)
    {
        var tcs = new TaskCompletionSource<string>();

        DownloadStringCompletedEventHandler handler = null;
        handler = (sender, e) =>
            {
                client.DownloadStringCompleted -= handler;

                if (e.Error != null)
                {
                    tcs.SetException(e.Error);
                }
                else
                {
                    tcs.SetResult(e.Result);
                }
            };

        client.DownloadStringCompleted += handler;
        client.DownloadStringAsync(address);

        return tcs.Task;
    }
}

用法:

async void DownloadExample()
{
    WebClient client = new WebClient();
    await client.DownloadStringTask(new Uri("http://http://stackoverflow.com/questions/13266079/"));
}