c# - Visual Studio 报告并非所有代码路径都返回值，即使它们返回值

Question

我在 NETMF C# 中有一个我正在编写的 API，其中包含一个发送 HTTP 请求的函数。对于熟悉 NETMF 的人来说，这是“webClient”示例的重大修改版本，它是一个演示如何提交 HTTP 请求并接收响应的简单应用程序。在示例中，它只是打印响应并返回 void,。然而，在我的版本中，我需要它来返回 HTTP 响应。

出于某种原因，Visual Studio 报告并非所有代码路径都返回一个值，尽管据我所知，它们确实返回了一个值。

这是我的代码...

  /// <summary>
  /// This is a modified webClient
  /// </summary>
  /// <param name="url"></param>
  private string httpRequest(string url)
  {
   // Create an HTTP Web request.
   HttpWebRequest request = HttpWebRequest.Create(url) as HttpWebRequest;

   // Set request.KeepAlive to use a persistent connection. 
   request.KeepAlive = true;

   // Get a response from the server.
    WebResponse resp = request.GetResponse();

   // Get the network response stream to read the page data.
   if (resp != null)
   {
    Stream respStream = resp.GetResponseStream();
    string page = "";
    byte[] byteData = new byte[4096];
    char[] charData = new char[4096];
    int bytesRead = 0;
    Decoder UTF8decoder = System.Text.Encoding.UTF8.GetDecoder();
    int totalBytes = 0;

    // allow 5 seconds for reading the stream
    respStream.ReadTimeout = 5000;

    // If we know the content length, read exactly that amount of 
    // data; otherwise, read until there is nothing left to read.
    if (resp.ContentLength != -1)
    {
     for (int dataRem = (int)resp.ContentLength; dataRem > 0; )
     {
      Thread.Sleep(500);
      bytesRead = respStream.Read(byteData, 0, byteData.Length);

      if (bytesRead == 0)
       throw new Exception("Data laes than expected");

      dataRem -= bytesRead;

      // Convert from bytes to chars, and add to the page 
      // string.
      int byteUsed, charUsed;
      bool completed = false;
      totalBytes += bytesRead;
      UTF8decoder.Convert(byteData, 0, bytesRead, charData, 0,
       bytesRead, true, out byteUsed, out charUsed,
       out completed);
      page = page + new String(charData, 0, charUsed);
     }

     page = new String(System.Text.Encoding.UTF8.GetChars(byteData));
    }
    else
     throw new Exception("No content-Length reported");

    // Close the response stream.  For Keep-Alive streams, the 
    // stream will remain open and will be pushed into the unused 
    // stream list.
    resp.Close();
    return page;
   }
  }

有什么想法吗？谢谢...

Answer 1

很明显，如果 (resp == null) 那么你仍然需要返回一些东西......