WP8中使用async/await扩展HttpWebRequest

浏览数：41 / 时间：2015年06月09日

前文讲到WP8中使用Async执行HTTP请求，用了微软提供的扩展。下面提供了一种方法，自己实现HttpWebRequest的扩展。

  
    
    namespace 
HttpExtensions
{
    public 
static class WebRequestExtensions
    {
        public 
async static 
Task<WebResponse> GetResponseAsync(this 
HttpWebRequest request)
        {
            var 
tcs = new 
TaskCompletionSource<WebResponse>();
 
            try
            {
                request.BeginGetResponse((ar) =>
                {
                    var 
response = request.EndGetResponse(ar);
                    tcs.SetResult(response);
                }, null);
            }
            catch 
(WebException we)
            {
                tcs.SetException(we);
            }
 
            return 
await tcs.Task;
        }
 
        public 
async static 
Task<WebResponse> GetResponseAsync(this 
HttpWebRequest request, string 
post)
        {
            var 
tcs = new 
TaskCompletionSource<WebResponse>();
 
            try
            {
                request.BeginGetRequestStream((arReq) =>
                {
                    var 
stream = request.EndGetRequestStream(arReq);
                    using 
(StreamWriter writer = new 
StreamWriter(stream))
                    {
                        writer.Write(post);
                        writer.Flush();
                    }
 
                    request.BeginGetResponse((ar) =>
                    {
                        var 
response = request.EndGetResponse(ar);
                        tcs.SetResult(response);
                    }, null);
                }, null);
            }
            catch 
(WebException we)
            {
                tcs.SetException(we);
            }
 
            return 
await tcs.Task;
        }
    }
}