我正在使用HttpWebRequest來調用Web服務。如果來自BeginGetResponse的AsyncCallback引發錯誤,我想將它傳播到我的主程序流程中。我在這樣做時遇到了麻煩,因爲錯誤不會傳播到AsyncCallback之外。我試過在HttpWebRequest鏈的每一步放置try/catch塊,但它永遠不會傳播超出「ResponseCallBack」方法。是否有可能回到主線程?WP7從BeginGetResponse回調中傳播異常
private void StartRequest()
{
// Code to create request object is here
// ...
httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), httpRequest);
}
private void GetRequestStreamCallback(IAsyncResult result)
{
HttpWebRequest request = (HttpWebRequest)result.AsyncState;
// End the operation
var postStream = request.EndGetRequestStream(result);
string body = GenerateRequestBody();
// Convert the string into a byte array
byte[] postBytes = Encoding.UTF8.GetBytes(body);
// Write to request stream
postStream.Write(postBytes, 0, postBytes.Length);
postStream.Close();
// Start the asynchronous operation to get the resonse
try
{
request.BeginGetResponse(new AsyncCallback(ResponseCallback), request);
}
catch (Exception)
{
throw;
}
}
private void ResponseCallback(IAsyncResult result)
{
string contents = String.Empty;
HttpWebRequest request = (HttpWebRequest)result.AsyncState;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(result);
using (Stream stream = response.GetResponseStream())
using (StreamReader reader = new StreamReader(stream))
{
contents = reader.ReadToEnd();
}
// Check the status
if (response.StatusCode == HttpStatusCode.OK)
{
//EXCEPTION NEVER MAKES IT PASSED HERE, EVEN IF I HAVE IT IN A TRY/CATCH BLOCK AND RE-THROW IT.
_object = ProcessResponseEntity(contents);
}
}