c# - 网络客户端错误(随机且非常烦人)

Question

WebClient wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
wc.OpenReadAsync(new Uri(url, UriKind.RelativeOrAbsolute));


void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{ 
  if (e.Error != null || e.Cancelled)
  {
    //randomly, this code gets hit and 
    //there is no inner exception - just says "an exception occurred during a webclient request"

代码中描述的错误是随机发生的，如果之后发出相同的 webclient 请求，它就会起作用。或者，如果发出新的资源请求，则出现错误的旧资源请求现在出现在新请求之前……

这很奇怪，这里的任何专家都知道为什么会这样吗？

编辑:错误信息

System.Net.WebException: An exception occurred during a WebClient request. ---> System.Exception ---> System.Exception: Error HRESULT E_FAIL has been returned from a call to a COM component. at System.Net.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult) at System.Net.BrowserHttpWebRequest.<>c_DisplayClass5.b_4(Object sendState) at System.Net.AsyncHelper.<>c_DisplayClass2.b_0(Object sendState) --- End of inner exception stack trace --- at System.Net.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state) at System.Net.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at System.Net.WebClient.GetWebResponse(WebRequest request, IAsyncResult result) at System.Net.WebClient.OpenReadAsyncCallback(IAsyncResult result) --- End of inner exception stack trace ---

URL 是一个简单的字符串，计数不超过 200。

Answer 1

如果取消或生成错误，该代码将被命中。我怀疑你遇到了网络问题，所以我会启动 Fiddler并观察 HTTP 请求并确保您正确取回它们。