抛出WebException但永远不会被抓住

我有以下代码：

try { using (var myHttpWebResponse = (HttpWebResponse) httPrequestCreated.GetResponse()) { var streamResponse = myHttpWebResponse.GetResponseStream(); if (streamResponse != null) { var streamRead = new StreamReader(streamResponse); var readBuff = new Char[256]; var count = streamRead.Read(readBuff, 0, 256); while (count > 0) { var outputData = new String(readBuff, 0, count); finalResopnse += outputData; count = streamRead.Read(readBuff, 0, 256); } streamRead.Close(); streamResponse.Close(); myHttpWebResponse.Close(); } } } catch (WebException ex) { MessageBox.Show("something went wrong"); } 

错误代码是404 Not Found ，但不是MessageBox而是我收到以下错误：

为什么exception从未被捕获？

Answer 1

您可能在Visual Studio中启用了第一次机会exception捕获。

尝试在没有调试器的情况下运行应用程序（Ctrl + F5）。 或者，如果您收到此对话框，则可以按“运行”（F5）获取消息框。

Answer 2

你确定你“抓住”同一类型的例外吗？ 而不是WebException只捕获Exception ，看看你是否得到了MessageBox

  try { using (var myHttpWebResponse = (HttpWebResponse) httPrequestCreated.GetResponse()) { var streamResponse = myHttpWebResponse.GetResponseStream(); if (streamResponse != null) { var streamRead = new StreamReader(streamResponse); var readBuff = new Char[256]; var count = streamRead.Read(readBuff, 0, 256); while (count > 0) { var outputData = new String(readBuff, 0, count); finalResopnse += outputData; count = streamRead.Read(readBuff, 0, 256); } streamRead.Close(); streamResponse.Close(); myHttpWebResponse.Close(); } } } catch (Exception ex) { MessageBox.Show(string.format("this went wrong: {0}", ex.Message)); } 

编辑 ：看着你仔细观察我认为你看到之前的exception被抛到了你的catch区块。 在你的VS上按Ctrl + Alt + E并确保未选中 Common Language Runtime Exceptions的Throw检查