在 MVC 中使用自定义 404 页面的自定义路由

Question

我设置了自定义路线：

var tradeCategoriesRoute = routes.MapRoute(
     name: "TradeCategoriesIndex",
     url: "TradeCategories/{*categories}",
     defaults:
          new
          {
                controller = "TradeCategories",
                action = "Index"
          },
          namespaces: new[] {"Website.Controllers"}
);
tradeCategoriesRoute.DataTokens["UseNamespaceFallback"] = false;
tradeCategoriesRoute.RouteHandler = new CategoriesRouteHandler();

我还在 Global.asax 中设置了自定义 404 页面：

private void Application_Error(object sender, EventArgs e)
{
    var exception = Server.GetLastError();
    var httpException = exception as HttpException;
    DisplayErrorPage(httpException);
}

private void DisplayErrorPage(HttpException httpException)
{
    Response.Clear();
    var routeData = new RouteData();

    if (httpException != null && httpException.GetHttpCode() == 404)
    {
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("action", "Missing");
    }
    else if (httpException != null && httpException.GetHttpCode() == 500)
    {
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("action", "Index");
        routeData.Values.Add("status", httpException.GetHttpCode());
    }
    else
    {
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("action", "Index");
        routeData.Values.Add("status", 500);
    }
    routeData.Values.Add("error", httpException);
    Server.ClearError();
    Response.TrySkipIisCustomErrors = true;
    IController errorController = ObjectFactory.GetInstance<ErrorController>();
    errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
    Response.End();
}

看来我真正的问题是我制作的自定义路由处理程序：

public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
    IRouteHandler handler = new MvcRouteHandler();
    var values = requestContext.RouteData.Values;
    if (values["categories"] != null)
        values["categoryNames"] = values["categories"].ToString().Split('/').Where(x => !string.IsNullOrWhiteSpace(x)).ToArray();
    else
        values["categoryNames"] = new string[0];
    return handler.GetHttpHandler(requestContext);
}

它可以正常工作并正确显示“/doesnotexist”之类的路线的 404 页面，但不适用于“/TradeCategories/doesnotexist”之类的路线。相反，我得到一个内置的 404 页面，其中显示消息“您要查找的资源已被删除、名称已更改或暂时不可用。”。

如何让我的自定义 404 页面与这些自定义路由一起使用？

Answer 1

您可能想要研究的是 TradeCategories 控制器的 Index 操作的实现。自定义路由和自定义处理程序看起来基本上可以匹配任何路由（TradeCategories/*），所以我猜测您的操作或视图中的某些内容正在返回 404 而不会引发可以在 global.asax 中捕获的异常？

Answer 2

您需要覆盖 GLobal.asax 中的 Application_Error 方法

来自link：

void Application_Error(object sender, EventArgs e)
{
  // Code that runs when an unhandled error occurs

  // Get the exception object.
  Exception exc = Server.GetLastError();

  // Handle HTTP errors
  if (exc.GetType() == typeof(HttpException))
  {
    // The Complete Error Handling Example generates
    // some errors using URLs with "NoCatch" in them;
    // ignore these here to simulate what would happen
    // if a global.asax handler were not implemented.
      if (exc.Message.Contains("NoCatch") || exc.Message.Contains("maxUrlLength"))
      return;

    //Redirect HTTP errors to HttpError page
    Server.Transfer("HttpErrorPage.aspx");
  }

  // For other kinds of errors give the user some information
  // but stay on the default page
  Response.Write("<h2>Global Page Error</h2>\n");
  Response.Write(
      "<p>" + exc.Message + "</p>\n");
  Response.Write("Return to the <a href='Default.aspx'>" +
      "Default Page</a>\n");

  // Log the exception and notify system operators
  ExceptionUtility.LogException(exc, "DefaultPage");
  ExceptionUtility.NotifySystemOps(exc);

  // Clear the error from the server
  Server.ClearError();
}

这应该可行。但是，我宁愿重定向到不同的页面，而不是写信给Response。

类似this:

IController controller = new ErrorPageController();
    controller.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
    Response.End();