Handling Exception in Global.asax in MVC

Instead of writing the try and catch throughout the application, global.asax , application_error method is the common place to handle all the error and based on the type of exception it will redirect to the page.

Code snippet : For Gloab.asax page

·         Exception ex = Server.GetLastError();

It helps to get the last exception of the application that application find.

·         routeData.Values.Add("controller", "Error");

Registered the controller error for routing data.

·         Now here it is checking the types of error got in application as 401, 404 etc

             if (((HttpException)ex).GetHttpCode() == 404)

         {

                 routeData.Values.Add("action", "PageNotFound");

    }

·         Final code to execute the controller requert and redire t to particular controller and action.

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

protected void Application_Error(object sender, EventArgs e)

        {

            Exception ex = Server.GetLastError();

            RouteData routeData = new RouteData();

            routeData.Values.Add("controller", "Error");

            Guid ErrorId = Guid.NewGuid();

            routeData.Values.Add("ErrorId", ErrorId);

            Response.Clear();

            if (ex is HttpException)

            {

                if (((HttpException)ex).GetHttpCode() == 404)

                {

                    routeData.Values.Add("action", "PageNotFound");

                }

                else if (((HttpException)ex).GetHttpCode() == 401)

                {

                    routeData.Values.Add("action", "UnAuthorized");

                }

                else

                {

                    routeData.Values.Add("ErrorValue", ex);

                    routeData.Values.Add("action", "Index");

                }

            }

            else if (ex is Exception)

            {

                routeData.Values.Add("ErrorValue", ex);

                routeData.Values.Add("action", "Index");

            }

            // LogHelper.ErrorLog(ErrorId.ToString(),ex);

            //Clear error in server

            Server.ClearError();

            Response.TrySkipIisCustomErrors = true;

            // Call the target controller and pass the route data

            IController errorController = new WebApplication2.Controllers.ErrorController();

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

        }

Code snippet : For Error controller to get details in MVC

We will have three different action to handle three different type of error as 404, 401 and server error.

·         Code will use to get the exception detail in server side exception and which will use to display in DIV

Exception exception = this.RouteData.Values["ErrorValue"] != null ? (Exception)this.RouteData.Values["ErrorValue"] : null;

·         It converts the request type to html to display in the page.

Response.ContentType = "text/html";

public class ErrorController : Controller

    {

        // GET: Error

        public ActionResult Index()

        {

            Response.ContentType = "text/html";

            try

            {

                Exception exception = this.RouteData.Values["ErrorValue"] != null ? (Exception)this.RouteData.Values["ErrorValue"] : null;

                string errorId = this.RouteData.Values["ErrorId"].ToString();

                string message = exception != null ? exception.Message.ToString() : "Undefined Error";

                string stackTrace = exception.StackTrace.ToString();

                ViewBag.ErrorId = errorId;

                ViewBag.Message = message;

                ViewBag.StackTrace = stackTrace;

            }

            catch (Exception ex)

            {

                Guid ErrorId = Guid.NewGuid();

                ViewBag.ErrorId = ErrorId;

                ViewBag.Message = ex.Message.ToString();

                ViewBag.StackTrace = ex.StackTrace.ToString();

                // LogHelper.ErrorLog(ErrorId.ToString(),ex);

            }

            return View();

        }

        public ActionResult PageNotFound()

        {

            Response.ContentType = "text/html";

            return View();

        }

        public ActionResult UnAuthorized()

        {

            Response.ContentType = "text/html";

            return View();

        }

    }

Code snippet : For Server side exceptions in MVC for Index.cshtml

·         It Use to hide and show the actual error from outside.

<a href="javascript:void(0)" onclick="ShowErrorDetail();" style="text-decoration:none">@ViewBag.ErrorId</a>

<div class="form-group">

    <div class="row">

        <div class="col-md-10 col-md-offset-1 headerText">

            Technical Fault

        </div>

    </div>

    <br /><br />

    <div class="col-lg-12 col-sm-12 col-md-12">

        <div class="form-group text-center">

            <div class="alert alert-info" style="font-size:14px;font-weight:bold;">

                Please retry the same operation again. If you are facing problem concistently please contact administrator with below Id.

                <br />

                <a href="javascript:void(0)" onclick="ShowErrorDetail();" style="text-decoration:none">@ViewBag.ErrorId</a>

            </div>

        </div>

    </div>

    <br />

    <div class="col-lg-12 col-sm-12 col-md-12">

        <div class="form-group text-center" id="ErrorDetail" style="display:none">

            <div class="alert alert-danger">

                <b>@ViewBag.Message</b>

                @ViewBag.StackTrace

            </div>

        </div>

    </div>

</div>

<script type="text/javascript">

    function ShowErrorDetail()

    {

        $("#ErrorDetail").toggle();

    }

</script>

Onclicking the Unique Id it will look like below.