从System.Net.WebRequest获取完整的响应体

我使用System.Net.WebRequest从一些API获取信息。当我得到一个错误时，响应只包含基本的HttpStatusCode和消息，而不包含返回的完整错误。相比之下，在诸如POSTMAN之类的工具中运行相同的post数据和header将返回来自该API的完整错误。

我想知道是否有一些属性或方式我可以得到完整的错误响应?

下面是我正在运行的代码:

public HttpStatusCode GetRestResponse(
    string verb,
    string requestUrl,
    string userName,
    string password,
    out string receiveContent,
    string postContent = null)
{
    var request = (HttpWebRequest)WebRequest.Create(requestUrl);
    request.Method = verb;
    if (!string.IsNullOrEmpty(userName))
    {
        string authInfo = string.Format("{0}:{1}", userName, password);
        authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
        request.Headers.Add("Authorization", "Basic " + authInfo);
    }
    if (!string.IsNullOrEmpty(postContent))
    {
        byte[] byteArray = Encoding.UTF8.GetBytes(postContent);
        request.ContentType = "application/json; charset=utf-8";
        request.ContentLength = byteArray.Length;
        var dataStream = request.GetRequestStream();
        dataStream.Write(byteArray, 0, byteArray.Length);
        dataStream.Close();
    }
    try
    {
        using (WebResponse response = request.GetResponse())
        {
            var responseStream = response.GetResponseStream();
            if (responseStream != null)
            {
                var reader = new StreamReader(responseStream);
                receiveContent = reader.ReadToEnd();
                reader.Close();
                return ((HttpWebResponse) response).StatusCode;
            }
        }
    }
    catch (Exception ex)
    {
        receiveContent = string.Format("{0}'n{1}'nposted content = 'n{2}", ex, ex.Message, postContent);
        return HttpStatusCode.BadRequest;
    }
    receiveContent = null;
    return 0;
}

当我生成一个向我展示错误的请求时，我得到的错误消息是:The remote server returned an error: (400) Bad Request.和没有InnerException，并且没有任何其他我可以从异常中受益的东西。

[Answer] @Rene指出了正确的方向，可以像这样获得适当的响应体:

var reader = new StreamReader(ex.Response.GetResponseStream());
var content = reader.ReadToEnd();

catch (WebException e)
{
    var response = ((HttpWebResponse)e.Response);
    var someheader = response.Headers["X-API-ERROR"];
    // check header
    if (e.Status == WebExceptionStatus.ProtocolError)
    {
        // protocol errors find the statuscode in the Response
        // the enum statuscode can be cast to an int.
        int code = (int) ((HttpWebResponse)e.Response).StatusCode;
        string content;
        using(var reader = new StreamReader(e.Response.GetResponseStream()))
        {
            content = reader.ReadToEnd();
        }
        // do what ever you want to store and return to your callers
    }
}