asp.net - 如何在自定义错误页面中访问 HTTP StatusDescription

Question

当操作 (asp.net mvc 5) 在数据库中找不到某些内容时，用户必须看到带有简短自定义错误消息的页面，例如"Invoice 5 does not exist" .此外，响应必须有 404 HTTP 代码。
另一个例子:当 Action 被不正确地调用时，用户必须看到例如"Parameter 'invoiceId' is required" .此外，响应必须有 400 HTTP 代码。
我尝试将自定义消息存储在 HTTP 状态描述中并在自定义错误页面中显示它们。有两种方法(afaik):
一种

mvc action:
return HttpNotFound("Invoice 5 does not exist"); OR
return new HttpStatusCodeResult(HttpStatusCode.BadRequest, "Parameter 'invoiceId' is required");

web.config:
<httpErrors errorMode="Custom">
  <remove statusCode="404" />
  <error statusCode="404" path="/Error/NotFound" responseMode="ExecuteURL" />
  <remove statusCode="400" />
  <error statusCode="400" path="/Error/BadRequest" responseMode="ExecuteURL" />
</httpErrors>

乙

mvc action:
throw new HttpException(404, "Invoice 5 does not exist"); OR
throw new HttpException(400, "Parameter 'invoiceId' is required");

web.config:
<customErrors mode="On">
  <error statusCode="404" redirect="~/Error/NotFound" />
  <error statusCode="400" redirect="~/Error/BadRequest" />
</customErrors>

无论哪种方式，如何在自定义页面中显示 HTTP 状态描述？如何在 NotFound/BadRequest 操作或 View 中访问它？
如果这是不可能的，那么 4xx 响应如何包含数据驱动的消息，很好地呈现给用户？
更新:
我沉迷于使用配置，但似乎不可能将自定义字符串推送到 web.config 中声明的错误页面。 @Carl 和 @V2Solutions 都只回答了我的后备问题(从“如果这是不可能的……”开始)。我会这样总结他们的方法:
C(@卡尔)

Don't use web.config or HttpStatusCodeResult.

Throw exceptions, catch them in Application_Error and render custom error pages programmatically.

D (@V2Solutions)

Don't use web.config, exceptions, or HttpStatusCodeResult.

Set the status code/description directly in the Response and return whatever view you like.

Answer 1

创建一个 ErrorController - 这允许您定制最终用户的错误页面和状态代码。每个操作结果都接受一个异常，您可以将其添加到 global.asax 的 application_error 方法中的路由数据中。它不必是异常对象，它可以是您喜欢的任何东西——只需将它添加到 application_error 中的路由数据即可。

[AllowAnonymous]
public class ErrorController : Controller
{
    public ActionResult PageNotFound(Exception ex)
    {
        Response.StatusCode = 404;
        return View("Error", ex);
    }

    public ActionResult ServerError(Exception ex)
    {
        Response.StatusCode = 500;
        return View("Error", ex);
    }

    public ActionResult UnauthorisedRequest(Exception ex)
    {
        Response.StatusCode = 403;
        return View("Error", ex);
    }

    //Any other errors you want to specifically handle here.

    public ActionResult CatchAllUrls()
    {
        //throwing an exception here pushes the error through the Application_Error method for centralised handling/logging
        throw new HttpException(404, "The requested url " + Request.Url.ToString() + " was not found");
    }
}

您的错误 View :

@model Exception
@{
    ViewBag.Title = "Error";
}

<h2>Error</h2>

@Model.Message

添加一个路由以将所有 url 捕获到路由配置的末尾 - 这将捕获通过匹配现有路由尚未捕获的所有 404:

routes.MapRoute("CatchAllUrls", "{*url}", new { controller = "Error", action = "CatchAllUrls" });

在您的 global.asax 中:

protected void Application_Error(object sender, EventArgs e)
    {
        Exception exception = Server.GetLastError();

        //Error logging omitted

        HttpException httpException = exception as HttpException;
        RouteData routeData = new RouteData();
        IController errorController = new Controllers.ErrorController();
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("area", "");
        routeData.Values.Add("ex", exception);

        if (httpException != null)
        {
            //this is a basic example of how you can choose to handle your errors based on http status codes.
            switch (httpException.GetHttpCode())
            {
                case 404:
                    Response.Clear();

                    // page not found
                    routeData.Values.Add("action", "PageNotFound");

                    Server.ClearError();
                    // Call the controller with the route
                    errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));

                    break;
                case 500:
                    // server error
                    routeData.Values.Add("action", "ServerError");

                    Server.ClearError();
                    // Call the controller with the route
                    errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
                    break;
                 case 403:
                    // server error
                    routeData.Values.Add("action", "UnauthorisedRequest");

                    Server.ClearError();
                    // Call the controller with the route
                    errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
                    break;
                 //add cases for other http errors you want to handle, otherwise HTTP500 will be returned as the default.
                default:
                    // server error
                    routeData.Values.Add("action", "ServerError");

                    Server.ClearError();
                    // Call the controller with the route
                    errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
                    break;
            }
        }
        //All other exceptions should result in a 500 error as they are issues with unhandled exceptions in the code
        else
        {
            routeData.Values.Add("action", "ServerError");
            Server.ClearError();
            // Call the controller with the route
            errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
        }
    }

然后当你扔

throw new HttpException(404, "Invoice 5 does not exist");

您的消息将被传递并显示给用户。此时可以指定要使用的状态代码，并扩展 application_error 中的 switch 语句。