c# http Post 在 webresponse 中没有得到任何内容

这是我的请求和响应代码。

System.IO.MemoryStream xmlStream = null;
HttpWebRequest HttpReq = (HttpWebRequest)WebRequest.Create(url); 
xmlStream = new System.IO.MemoryStream(System.Text.Encoding.UTF8.GetBytes(format));

byte[] buf2 = xmlStream.ToArray();
System.Text.UTF8Encoding UTF8Enc = new System.Text.UTF8Encoding();
string s = UTF8Enc.GetString(buf2);
string sPost = "XMLData=" + System.Web.HttpUtility.UrlDecode(s);
byte[] bPostData =  UTF8Enc.GetBytes(sPost);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); 
request.ContentType = "application/x-www-form-urlencoded";
HttpReq.Timeout = 30000;  
request.Method = "POST"; 
request.KeepAlive = true; 
using (Stream requestStream = request.GetRequestStream()) 
{
    requestStream.Write(bPostData, 0, bPostData.Length); 
    requestStream.Close(); 
}

string responseString = "";
HttpWebResponse response = (HttpWebResponse)request.GetResponse(); 
using (StreamReader sr = new StreamReader(response.GetResponseStream())) 
{ 
    responseString = sr.ReadToEnd(); 
}

此代码的任何部分都不会崩溃。 “format”字符串是其中包含 XML 的字符串。最后当你尝试查看里面有什么时responseString，它是一个空字符串。我应该看到从 URL 发回给我的 XML。这段代码中是否缺少某些内容？

我建议简化这个混乱的代码：

using (var client = new WebClient())
{
    var values = new NameValueCollection
    {
        { "XMLData", format }
    };
    byte[] resultBuffer = client.UploadValues(url, values);
    string result = Encoding.UTF8.GetString(resultBuffer);
}

如果您想直接在 POST 正文中上传 XML，则不应使用application/x-www-form-urlencoded作为内容类型。您可能应该指定正确的内容类型，如下所示：

using (var client = new WebClient())
{
    client.Headers[HttpRequestHeader.ContentType] = "text/xml";
    var data = Encoding.UTF8.GetBytes(format);
    byte[] resultBuffer = client.UploadData(url, data);
    string result = Encoding.UTF8.GetString(resultBuffer);
}