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ASP.NET MVC Custom Error Handling Application_Error Global.asax?

Asked 2009-07-23T11:07:04.733
111

I have some basic code to determine errors in my MVC application. Currently in my project I have a controller called Error with action methods HTTPError404(), HTTPError500(), and General(). They all accept a string parameter error. Using or modifying the code below. What is the best/proper way to pass the data to the Error controller for processing? I would like to have a solution as robust as possible.

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

    HttpException httpException = exception as HttpException;
    if (httpException != null)
    {
        RouteData routeData = new RouteData();
        routeData.Values.Add("controller", "Error");
        switch (httpException.GetHttpCode())
        {
            case 404:
                // page not found
                routeData.Values.Add("action", "HttpError404");
                break;
            case 500:
                // server error
                routeData.Values.Add("action", "HttpError500");
                break;
            default:
                routeData.Values.Add("action", "General");
                break;
        }
        routeData.Values.Add("error", exception);
        // clear error on server
        Server.ClearError();

        // at this point how to properly pass route data to error controller?
    }
}
c# asp.net asp.net-mvc error-handling user-experience
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1 Answer

31

To answer the initial question "how to properly pass routedata to error controller?":

IController errorController = new ErrorController();
errorController.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));

Then in your ErrorController class, implement a function like this:

[AcceptVerbs(HttpVerbs.Get)]
public ViewResult Error(Exception exception)
{
    return View("Error", exception);
}

This pushes the exception into the View. The view page should be declared as follows:

<%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage<System.Exception>" %>

And the code to display the error:

<% if(Model != null) { %>  <p><b>Detailed error:</b><br />  <span class="error"><%= Helpers.General.GetErrorMessage((Exception)Model, false) %></span></p> <% } %>

Here is the function that gathers the all exception messages from the exception tree:

    public static string GetErrorMessage(Exception ex, bool includeStackTrace)
    {
        StringBuilder msg = new StringBuilder();
        BuildErrorMessage(ex, ref msg);
        if (includeStackTrace)
        {
            msg.Append("\n");
            msg.Append(ex.StackTrace);
        }
        return msg.ToString();
    }

    private static void BuildErrorMessage(Exception ex, ref StringBuilder msg)
    {
        if (ex != null)
        {
            msg.Append(ex.Message);
            msg.Append("\n");
            if (ex.InnerException != null)
            {
                BuildErrorMessage(ex.InnerException, ref msg);
            }
        }
    }
answered 2010-01-12T13:55:10.783

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