Question

我正在使用线程池调用一些异步Web请求调用来发布数据

我在for循环中调用RunWebAccess函数

public void RunWebAccess (string strdara, int inttype)
{
     HttpWebRequest req = 
         (HttpWebRequest)WebRequest.Create("http://www.test.com");           
     byte[] requestBytes = System.Text.Encoding.ASCII.GetBytes(xmlvar);
     req.Method = "POST";
     req.ContentType = "text/xml";
     req.ContentLength = requestBytes.Length;         
     IAsyncResult result = 
         req.BeginGetRequestStream(new AsyncCallback(ProcessResults), req);
}

private void ProcessResults(IAsyncResult result)
{ 
    HttpWebRequest request = (HttpWebRequest)result.AsyncState;
    Stream postStream = request.EndGetRequestStream(result);
    postStream.Write(result., 0, postData.Length ;
    postStream.Close();
}

ProcessResults 功能无效，因为它无法访问参数。

问题是我想在ProcessResults函数中传递参数并写入流。

根据代码，我不能在ProcessResults函数中使用全局变量或读取输入（我想在ProcessResults函数中传递strdara，inttype）

Answer 1

您可以使用lambda-notation进行回调，如下所示：

public void RunWebAccess (string strdara, int inttype)
{
     HttpWebRequest req = 
         (HttpWebRequest)WebRequest.Create("http://www.test.com");           
     byte[] requestBytes = System.Text.Encoding.ASCII.GetBytes(xmlvar);
     req.Method = "POST";
     req.ContentType = "text/xml";
     req.ContentLength = requestBytes.Length;
     IAsyncResult result = null;
     result = 
         req.BeginGetRequestStream(ar =>
         {
            Stream postStream = request.EndGetRequestStream(result);
            postStream.Write(result., 0, postData.Length ;
            postStream.Close();
         }
         , req);
}

Answer 2

您可以发送一个新对象，其中包含要传递给回调的所有参数。喜欢：

IAsyncResult result = req.BeginGetRequestStream(
    new AsyncCallback(ProcessResults),
    new Tuple<HttpWebRequest,byte[]>(req, postData));

将参数传递给BeginGetRequestStream

2 个答案: