Exceptions In MVC

(7 methods explained)
　
Method 1:- Simple way

Method 2:- Override "OnException" method

Method 3:- Using "HandleError" Attribute

Method 4:- Inheriting from "HandleErrorAttribute"

Method 5:- Handling HTTP errors

Method 6:- Global Error handling in MVC

Method 7 : Should create a log file in the system

　

Method 1:- Simple way
But if we use this method then we will not be utilizing MVC exception mechanismproperly and completely.
public ActionResult SomeError() { try {} catch(Exception ex) {return View("Error");} } 


Controller.

 View

Output:

Method 2:- Override “OnException” method

This approach is used when we want to handle all the exceptions across the Action methods at the controller level.
Controller
 public ActionResult Test()
        {
            int x = 1, y = 0;
            int z = x % y;
            return View();
        }
        protected override void OnException(ExceptionContext filterContext)
        {
            Exception ex = filterContext.Exception;
            filterContext.ExceptionHandled = true;
            var model = new HandleErrorInfo(filterContext.Exception, "Controller", "Action");
            filterContext.Result = new ViewResult()
            {
                ViewName = "Error",
                ViewData = new ViewDataDictionary(model.Exception.Message)
            };
        }
        public ActionResult Error()
        {
            return View();
        }
        // GET: Home
        public ActionResult Index()
        {
                int x = 1, y = 0;
                int z = x % y;
                return View();
        }
 

Output:

Second Example:

protected override void OnException(ExceptionContext filterContext)
        {
            if (filterContext.ExceptionHandled || !filterContext.HttpContext.IsCustomErrorEnabled)
            {
                //return;
            }
            if (new HttpException(null, filterContext.Exception).GetHttpCode() != 500)
            {
                //return;
            }
            // if the request is AJAX return JSON else view.
            if (filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")
            {
                filterContext.Result = new JsonResult
                {
                    JsonRequestBehavior = JsonRequestBehavior.AllowGet,
                    Data = new
                    {
                        error = true,
                        message = filterContext.Exception.Message
                    }
                };
            }
            else
            {
                var controllerName = (string)filterContext.RouteData.Values["controller"];
                var actionName = (string)filterContext.RouteData.Values["action"];
                var model = new HandleErrorInfo(filterContext.Exception, controllerName, actionName);
                filterContext.Result = new ViewResult
                {
                    ViewName = "Error",
                    ViewData = new ViewDataDictionary<HandleErrorInfo>(model),
                    TempData = filterContext.Controller.TempData
                };
            }
            // log the error using log4net.
            //_logger.Error(filterContext.Exception.Message, filterContext.Exception);
            filterContext.ExceptionHandled = true;
            filterContext.HttpContext.Response.Clear();
            filterContext.HttpContext.Response.StatusCode = 500;
            filterContext.HttpContext.Response.TrySkipIisCustomErrors = true;
        }

In the View write the following code

Output:

The problem with this approach is we cannot reuse the error handling logic across multiple controllers.

Method 3:- Using “HandleError” Attribute

The other way of handling error is my using “HandleError” attribute. Implementing “HandleError” attribute is a two-step process:-

Step 1 :- We need to first decorate the action method with “HandleError” attribute as shown in the below code

public class HomeController : Controller
 {
        [HandleError()]
        public ActionResult SomeError()
        {
            throw new Exception("test");
        }
}


Step 2:- In the “Web.config” file you need to add the “customErrors” tag and point to the “Error” view as shown in the below “Web.config” code snippet.
Hide  

<system.web>
<customErrors defaultRedirect="Error.cshtml" mode="On">
</customErrors>
</system.web>

In case you want different error views for different exception types you can decorate action method with multiple “HandleError” attribute point to multiple views as per exception types.

public class HomeController : Controller
{
        [HandleError(ExceptionType=typeof(ArithmeticException),View="Arthimetic")]
[HandleError(ExceptionType = typeof(NotImplementedException),View ="Error1")]

public ActionResult SomeError()
{
   
}

}

Still working on it..............................