C#正在将文件上载到HTTPServer

我需要编写一个http客户端来使用http将一个巨大的文件上传到服务器。代码

public Stream function()
{
    string postData = "This is a test that posts this string to a Web server.";
    byte[] byteArray = Encoding.UTF8.GetBytes (postData);
    // Set the ContentType property of the WebRequest.
    request.ContentType = "application/x-www-form-urlencoded";
    // Set the ContentLength property of the WebRequest.
    request.ContentLength = byteArray.Length;
    request.Method = "POST";
    // Get the request stream.
    Stream dataStream = request.GetRequestStream ();
    // Write the data to the request stream.
    return dataStream;
}

然后，我将dataStream返回给该函数的调用方，以便应用程序继续使用write写入流。然后，一旦完成写入，就会调用GetResponse，然后关闭流。但我得到了异常

协议违反异常写入流时位于System.Net.HttpWriteStream.Write（）。

请帮忙。