当服务器返回错误时，使用WebClient访问响应主体的任何方法？

当使用WebClient类时响应状态为4xx时，是否有办法访问响应主体，例如：

(webClient, evt) => // this is the event handler for the UploadStringCompleted event { if (evt.Error != null) { // can I access the response text? } }); 

Answer 1

由于evt.Error是一个WebException（而不是一个vanillaexception），这就是我所做的（请原谅VB.NET）：

 ''' 
 ''' Extends a WebException to include any body text from the HTTP Response in the .Message ''' 
 Friend Function ExtendWebExceptionInfo(ex As Exception) As Exception Dim wEx As WebException = TryCast(ex, WebException) If wEx Is Nothing Then Return ex Dim exMessage As String = Nothing Using reader As New StreamReader(wEx.Response.GetResponseStream, System.Text.Encoding.UTF8) exMessage = reader.ReadToEnd End Using If Not String.IsNullOrWhiteSpace(exMessage) Then exMessage = String.Format("{0}{1}{1}The server says:{1}{2}", wEx.Message, vbCrLf, exMessage) Return New WebException(exMessage, wEx, wEx.Status, wEx.Response) End If Return wEx End Function