C# 如何从webclient获取状态代码？
我正在使用C# 如何从webclient获取状态代码？,c#,.net,vb.net,webclient,C#,.net,Vb.net,Webclient,我正在使用WebClient类将一些数据发布到web表单。我想获取表单提交的响应状态代码。到目前为止，我已经了解了如何在出现异常时获取状态代码 Catch wex As WebException If TypeOf wex.Response Is HttpWebResponse Then msgbox(DirectCast(wex.Response, HttpWebResponse).StatusCode) End If 但是，如果表
WebClientCatch wex As WebException
If TypeOf wex.Response Is HttpWebResponse Then
msgbox(DirectCast(wex.Response, HttpWebResponse).StatusCode)
End If
PS：我不喜欢使用httpwebrequest/httpwebresponse，我试过了。负责人不包括状态代码 如果我没有弄错的话，
WebClientHttpWebRequestHttpWebResponse不幸的是，状态代码没有出现在
ResponseHeadersprivate static int GetStatusCode(WebClient client, out string statusDescription)
{
FieldInfo responseField = client.GetType().GetField("m_WebResponse", BindingFlags.Instance | BindingFlags.NonPublic);
if (responseField != null)
{
HttpWebResponse response = responseField.GetValue(client) as HttpWebResponse;
if (response != null)
{
statusDescription = response.StatusDescription;
return (int)response.StatusCode;
}
}
statusDescription = null;
return 0;
}
您可以检查错误类型是否为
WebExceptionif (e.Error.GetType().Name == "WebException")
{
WebException we = (WebException)e.Error;
HttpWebResponse response = (System.Net.HttpWebResponse)we.Response;
if (response.StatusCode==HttpStatusCode.NotFound)
System.Diagnostics.Debug.WriteLine("Not found!");
}
if (e.Status == WebExceptionStatus.ProtocolError)
{
HttpWebResponse response = (HttpWebResponse)ex.Response;
if (response.StatusCode == HttpStatusCode.NotFound)
System.Diagnostics.Debug.WriteLine("Not found!");
}
Erik的答案在Windows Phone上不起作用。以下是：
class WebClientEx : WebClient
{
private WebResponse m_Resp = null;
protected override WebResponse GetWebResponse(WebRequest Req, IAsyncResult ar)
{
try
{
this.m_Resp = base.GetWebResponse(request);
}
catch (WebException ex)
{
if (this.m_Resp == null)
this.m_Resp = ex.Response;
}
return this.m_Resp;
}
public HttpStatusCode StatusCode
{
get
{
if (m_Resp != null && m_Resp is HttpWebResponse)
return (m_Resp as HttpWebResponse).StatusCode;
else
return HttpStatusCode.OK;
}
}
}
OpenReadAsyncxxxAsync此代码段中的回退代码为200，因为真正的HTTP错误（500、404等）无论如何都会报告为异常。这个技巧的目的是捕获非错误代码，在我的具体案例304（未修改）中。因此，回退假设，如果状态代码不知何故不可用，至少不会出错。您可以尝试使用此代码从WebException或OpenReadCompletedEventArgs.Error获取HTTP状态代码。它也适用于Silverlight，因为SL没有定义WebExceptionStatus.ProtocolError
HttpStatusCode GetHttpStatusCode(System.Exception err)
{
if (err is WebException)
{
WebException we = (WebException)err;
if (we.Response is HttpWebResponse)
{
HttpWebResponse response = (HttpWebResponse)we.Response;
return response.StatusCode;
}
}
return 0;
}
以防其他人需要上述黑客的F#版本
open System
open System.IO
open System.Net
type WebClientEx() =
inherit WebClient ()
[<DefaultValue>] val mutable m_Resp : WebResponse
override x.GetWebResponse (req: WebRequest ) =
x.m_Resp <- base.GetWebResponse(req)
(req :?> HttpWebRequest).AllowAutoRedirect <- false;
x.m_Resp
override x.GetWebResponse (req: WebRequest , ar: IAsyncResult ) =
x.m_Resp <- base.GetWebResponse(req, ar)
(req :?> HttpWebRequest).AllowAutoRedirect <- false;
x.m_Resp
member x.StatusCode with get() : HttpStatusCode =
if not (obj.ReferenceEquals (x.m_Resp, null)) && x.m_Resp.GetType() = typeof<HttpWebResponse> then
(x.m_Resp :?> HttpWebResponse).StatusCode
else
HttpStatusCode.OK
let wc = new WebClientEx()
let st = wc.OpenRead("http://www.stackoverflow.com")
let sr = new StreamReader(st)
let res = sr.ReadToEnd()
wc.StatusCode
sr.Close()
st.Close()
开放系统
开放系统
开放系统.Net
类型WebClientEx（）=
继承WebClient（）
[]val可变m_响应：WebResponse
覆盖x.GetWebResponse（请求：WebRequest）=
x、 m_Resp HttpWebRequest）。AllowAutoRedirect这是我用来扩展WebClient功能的。StatusCode和StatusDescription将始终包含最新的响应代码/描述
/// <summary>
/// An expanded web client that allows certificate auth and
/// the retrieval of status' for successful requests
/// </summary>
public class WebClientCert : WebClient
{
private X509Certificate2 _cert;
public WebClientCert(X509Certificate2 cert) : base() { _cert = cert; }
protected override WebRequest GetWebRequest(Uri address)
{
HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
if (_cert != null) { request.ClientCertificates.Add(_cert); }
return request;
}
protected override WebResponse GetWebResponse(WebRequest request)
{
WebResponse response = null;
response = base.GetWebResponse(request);
HttpWebResponse baseResponse = response as HttpWebResponse;
StatusCode = baseResponse.StatusCode;
StatusDescription = baseResponse.StatusDescription;
return response;
}
/// <summary>
/// The most recent response statusCode
/// </summary>
public HttpStatusCode StatusCode { get; set; }
/// <summary>
/// The most recent response statusDescription
/// </summary>
public string StatusDescription { get; set; }
}
返回的响应头是服务器头，如服务器、日期、pragma等。但是没有状态代码（200301404…）。对此感到抱歉，我有点惊讶地发现没有返回。如果您明确查找其他200系列消息（即201已创建-请参阅：），那么webrequest/ResponseEMS似乎是唯一的方法. :-/ 即使跳过了“中间”部分，如果能显式使用，那就太好了。@NormanH，我不反对。当涉及到状态代码时，WebClient似乎有点泄漏抽象。干杯非常感谢您的回答，它为我指出了获取响应头的正确方法-从WebException，而不是从WebClient.ResponseHeaders。是的，最好的方法实际上是在try-catch块中读取响应数据并捕获WebException。我这里遗漏了一些内容。“System.Exception”或“System.Net.Exception”均未包含“Error”的定义。如果调用成功，则不会出现异常（即返回2xx或3xx）。原来的海报是3xx，我在找204，其他人在找201。这并没有回答所问的问题。我不确定这个答案到目前为止是如何得到提升的，因为原始海报写道：“在没有引发异常的情况下，是否有某种方法可以获取状态代码？”我想现在没有必要进行下推表决。在Windows Phone上不起作用-GetWebResponse（）只存在于两种参数化风格中。仍然+1。有趣的是它不起作用。对我来说很有用，在更高答案中的反射没有（.NET 4.5 windows 7和10 app）FWIW，这在windows Phone上是不可能的，因为windows Phone不允许通过反射访问私人成员注意BindingFlags要求“使用System.reflection；”不错，但是有办法获取子状态代码吗？例如403.1或403.2？响应对象具有SubStatusCode属性。这是为什么？OP明确指出：但是如果表单提交成功并且没有引发异常…
这对我来说非常有效，因为我正在寻找响应代码。很好的解决方案！请注意，[与HttpClient不同]4xx和5xx响应会导致在“response=base.GetWebResponse（request）；”行引发WebException。您可以从异常中提取状态和响应（如果存在）。是。您仍然必须像正常情况一样捕获异常。但是，如果没有异常，这将暴露OP想要的内容。
HttpStatusCode GetHttpStatusCode(System.Exception err)
{
if (err is WebException)
{
WebException we = (WebException)err;
if (we.Response is HttpWebResponse)
{
HttpWebResponse response = (HttpWebResponse)we.Response;
return response.StatusCode;
}
}
return 0;
}
open System
open System.IO
open System.Net
type WebClientEx() =
inherit WebClient ()
[<DefaultValue>] val mutable m_Resp : WebResponse
override x.GetWebResponse (req: WebRequest ) =
x.m_Resp <- base.GetWebResponse(req)
(req :?> HttpWebRequest).AllowAutoRedirect <- false;
x.m_Resp
override x.GetWebResponse (req: WebRequest , ar: IAsyncResult ) =
x.m_Resp <- base.GetWebResponse(req, ar)
(req :?> HttpWebRequest).AllowAutoRedirect <- false;
x.m_Resp
member x.StatusCode with get() : HttpStatusCode =
if not (obj.ReferenceEquals (x.m_Resp, null)) && x.m_Resp.GetType() = typeof<HttpWebResponse> then
(x.m_Resp :?> HttpWebResponse).StatusCode
else
HttpStatusCode.OK
let wc = new WebClientEx()
let st = wc.OpenRead("http://www.stackoverflow.com")
let sr = new StreamReader(st)
let res = sr.ReadToEnd()
wc.StatusCode
sr.Close()
st.Close()
/// <summary>
/// An expanded web client that allows certificate auth and
/// the retrieval of status' for successful requests
/// </summary>
public class WebClientCert : WebClient
{
private X509Certificate2 _cert;
public WebClientCert(X509Certificate2 cert) : base() { _cert = cert; }
protected override WebRequest GetWebRequest(Uri address)
{
HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
if (_cert != null) { request.ClientCertificates.Add(_cert); }
return request;
}
protected override WebResponse GetWebResponse(WebRequest request)
{
WebResponse response = null;
response = base.GetWebResponse(request);
HttpWebResponse baseResponse = response as HttpWebResponse;
StatusCode = baseResponse.StatusCode;
StatusDescription = baseResponse.StatusDescription;
return response;
}
/// <summary>
/// The most recent response statusCode
/// </summary>
public HttpStatusCode StatusCode { get; set; }
/// <summary>
/// The most recent response statusDescription
/// </summary>
public string StatusDescription { get; set; }
}
byte[] response = null;
using (WebClientCert client = new WebClientCert())
{
response = client.UploadValues(postUri, PostFields);
HttpStatusCode code = client.StatusCode;
string description = client.StatusDescription;
//Use this information
}