Exception Handling

Handling un handled exception in .Net MVC application with Exception Filter is very easy thing to achieve.

There are ways to achieve 

Try/Catch:

     Putting our code inside try block and handling code inside catch block is something that every programmer know.

try{//our code}

catch{//handling code}

OnException Method:

   Controller class implements the IExceptionFilter.

We can override the OnException Method inside the controller class and can handle.

Attribute Based method:

Create an attribute that implements IExceptionFilter and use it over the method or class.

Global Handle Error:

Create an Handlr error attribute and register in filter config.

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace ERP.Attributes
{
    public class GlobalHandleErrorAttribute : HandleErrorAttribute
    {
     
        public override void OnException(ExceptionContext filterContext)
        {
            if (filterContext.ExceptionHandled /*|| !filterContext.HttpContext.IsCustomErrorEnabled*/)
            {
                return;
            }
            filterContext.ExceptionHandled = true;
            string spMessage = string.Empty;
            Exception exception = filterContext.Exception;
            if (exception is SqlException)//Get Exception Message raised by Stored procedure
            {
                SqlErrorCollection collection = (exception as SqlException).Errors;
                for (int i = 0; i < collection.Count; i++)
                {
                    if (!string.IsNullOrEmpty(collection[i].Procedure) && collection[i].LineNumber > 0)
                    {
                        spMessage = spMessage + collection[i].Message;
                    }
                }
            }
            if (IsAjax(filterContext) && !IsAcceptTextOrHtml(filterContext))//AJAX Call
            {
                string message = /*exception.GetType().Name + " : " +*/ (string.IsNullOrEmpty(spMessage) ?filterContext.Exception.Message : spMessage);
                filterContext.Result = new JsonResult()
                {

                    Data = new { Success = false, ErrorMessage = message, SuccessMessage = message, Message = message },
                    ContentEncoding = System.Text.Encoding.UTF8,
                    JsonRequestBehavior = JsonRequestBehavior.AllowGet
                };
            }
            else //Normal Call
            {
                string currentController = filterContext.RouteData.Values["controller"].ToString();
                string currentActionName = filterContext.RouteData.Values["action"].ToString();
                HandleErrorInfo handleErrorInfo = new HandleErrorInfo(exception, currentController, currentActionName);

                filterContext.Result = new ViewResult()
                {
                    ViewName = "~/Views/Shared/GlobalError.cshtml",
                    ViewData = new ViewDataDictionary(handleErrorInfo),
                };

            }

           
            base.OnException(filterContext);
        }

        private bool IsAjax(ExceptionContext filterContext)
        {
            return filterContext.HttpContext.Request.Headers["Accept"].ToLower().Contains("application/json") ||
            filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest" ||
            filterContext.HttpContext.Request.IsAjaxRequest();
        }

        private bool IsAcceptTextOrHtml(ExceptionContext filterContext)
        {
            return filterContext.HttpContext.Request.Headers["Accept"].ToLower().Contains("text/html");
        }
    }
}













using System.Web;
using System.Web.Mvc;

namespace ERP.WebApp
{
    public class FilterConfig
    {
        public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
            filters.Add(new GlobalHandleErrorAttribute());
            filters.Add(new GlobalActionFilterAttribute());
        }
    }
}