试试这个(这是vb代码:):

Try

Catch exp As WebException
  Dim sResponse As String = New StreamReader(exp.Response.GetResponseStream()).ReadToEnd
End Try

这为我解决了问题: https://gist.github.com/beccasaurus/929007/a8f820b153a1cfdee3d06a9c0a1d7ebfced8bb77

TL;博士: 问题: localhost返回预期的内容，远程IP更改400内容为“坏请求” 解决方案: 添加<httpErrors existingResponse="PassThrough"></httpErrors>到web.config/configuration/system。webServer为我解决了这个问题;现在所有服务器(本地和远程)返回完全相同的内容(由我生成)，而不管我返回的IP地址和/或HTTP代码。

扩展函数的异步版本:

    public static async Task<WebResponse> GetResponseAsyncNoEx(this WebRequest request)
    {
        try
        {
            return await request.GetResponseAsync();
        }
        catch(WebException ex)
        {
            return ex.Response;
        }
    }

我知道这个问题很久以前就有答案了，但我做了一个扩展方法，希望能帮助其他遇到这个问题的人。

代码:

public static class WebRequestExtensions
{
    public static WebResponse GetResponseWithoutException(this WebRequest request)
    {
        if (request == null)
        {
            throw new ArgumentNullException("request");
        }

        try
        {
            return request.GetResponse();
        }
        catch (WebException e)
        {
            if (e.Response == null)
            {
                throw;
            }

            return e.Response;
        }
    }
}

用法:

var request = (HttpWebRequest)WebRequest.CreateHttp("http://invalidurl.com");

//... (initialize more fields)

using (var response = (HttpWebResponse)request.GetResponseWithoutException())
{
    Console.WriteLine("I got Http Status Code: {0}", response.StatusCode);
}

试试这个(这是vb代码:):

Try

Catch exp As WebException
  Dim sResponse As String = New StreamReader(exp.Response.GetResponseStream()).ReadToEnd
End Try

我在尝试连接谷歌的OAuth2服务时也遇到了类似的问题。

我最终手动编写POST，而不是使用WebRequest，就像这样:

TcpClient client = new TcpClient("accounts.google.com", 443);
Stream netStream = client.GetStream();
SslStream sslStream = new SslStream(netStream);
sslStream.AuthenticateAsClient("accounts.google.com");

{
    byte[] contentAsBytes = Encoding.ASCII.GetBytes(content.ToString());

    StringBuilder msg = new StringBuilder();
    msg.AppendLine("POST /o/oauth2/token HTTP/1.1");
    msg.AppendLine("Host: accounts.google.com");
    msg.AppendLine("Content-Type: application/x-www-form-urlencoded");
    msg.AppendLine("Content-Length: " + contentAsBytes.Length.ToString());
    msg.AppendLine("");
    Debug.WriteLine("Request");
    Debug.WriteLine(msg.ToString());
    Debug.WriteLine(content.ToString());

    byte[] headerAsBytes = Encoding.ASCII.GetBytes(msg.ToString());
    sslStream.Write(headerAsBytes);
    sslStream.Write(contentAsBytes);
}

Debug.WriteLine("Response");

StreamReader reader = new StreamReader(sslStream);
while (true)
{  // Print the response line by line to the debug stream for inspection.
    string line = reader.ReadLine();
    if (line == null) break;
    Debug.WriteLine(line);
}

写入响应流的响应包含您要查找的特定错误文本。

特别是，我的问题是在url编码的数据块之间放置了端点。当我把它们拿出来的时候，一切都正常了。您可以使用类似的技术连接到您的服务并读取实际的响应错误文本。