How to access data after redirect - asp.net-mvc

Question

Again there are multiple articles which says how to access data after redirect. but doesn't serves my purpose.
I am having errorcontroller which is having index action method and error index view.
If there is any error in the application it will caught in Application_Error event.
inside Application_Error event I had logged the error and redirected to Error Index page like this -
protected new void Application_Error(object sender, EventArgs e)
{
Exception error = Server.GetLastError();
log.error(error.Message);
HttpContext.Current.Response.Redirect("~/Error/Index");
}
Now in the error index view, I would like to display the error message. What should I do in Application_Error event which can be access by Error Index view?
Updated : I don't want to use Session as session object may not be available in Application_Error event. this is dependent on when the error occurred.

Answer 1

Approach - 1
As per my knowledge you can use TempData to store the posted data. It is like a DataReader Class, once read, Data will be lost. So that stored data in TempData will become null.
var Value = TempData["keyName"] //Once read, data will be lost
So to persist the data even after the data is read you can Alive it like below
var Value = TempData["keyName"];
TempData.Keep(); //Data will not be lost for all Keys
TempData.Keep("keyName"); //Data will not be lost for this Key
TempData works in new Tabs/Windows also, like Session variable does.
You could use Session Variable also, Only major problem is that Session Variable are very heavy comparing with TempData. Finally you are able to keep the data across Controllers/Area also.
Approach - 2
This works for me. This is very easy and no need to consider any change in Web.Config or Register the Action Filter in Global.asax file.
ok. So, First I am creating a simple Action Filter. This will handle Ajax and Non Ajax requests.
public class MyCustomErrorAttribute : HandleErrorAttribute
{
public override void OnException(ExceptionContext filterContext)
{
filterContext.ExceptionHandled = true;
var debugModeMsg = filterContext.HttpContext.IsDebuggingEnabled
? filterContext.Exception.Message +
"\n" +
filterContext.Exception.StackTrace
: "Your error message";
//This is the case when you need to handle Ajax requests
if (filterContext.HttpContext.Request.IsAjaxRequest())
{
filterContext.Result = new JsonResult
{
JsonRequestBehavior = JsonRequestBehavior.AllowGet,
Data = new
{
error = true,
message = debugModeMsg
}
};
}
//This is the case when you handle Non Ajax request
else
{
var routeData = new RouteData();
routeData.Values["controller"] = "Error";
routeData.Values["action"] = "Error";
routeData.DataTokens["area"] = "app";
routeData.Values["exception"] = debugModeMsg;
IController errorsController = new ErrorController();
var exception = HttpContext.Current.Server.GetLastError();
var httpException = exception as HttpException;
if (httpException != null)
{
Response.StatusCode = httpException.GetHttpCode();
switch (System.Web.HttpContext.Current.Response.StatusCode)
{
case 504:
routeData.Values["action"] = "Http404";
break;
}
}
var rc = new RequestContext
(
new HttpContextWrapper(HttpContext.Current),
routeData
);
errorsController.Execute(rc);
}
base.OnException(filterContext);
}
}
Now you can implement this Action Filter on Controller as well as on the Action only.Example:
I am going little off topic. I thought this is bit important to explain.
If you pay attention to the above highlighted part. I have specified the order of the Action Filter. This basically describes the order of execution of Action Filter. This is a situation when you have multiple Action Filters implemented over Controller/Action Method
This picture just indicates that let's say you have two Action Filters. OnActionExecution will start to execute on Priority and OnActionExecuted will start from bottom to Top. That means in case of OnActionExecuted Action Filter having highest order will execute first and in case of OnActionExecuting Action Filter having lowest order will execute first. Example below.
public class Filter1 : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
//Execution will start here - 1
base.OnActionExecuting(filterContext);
}
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
//Execution will move here - 5
base.OnActionExecuted(filterContext);
}
}
public class Filter2 : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
//Execution will move here - 2
base.OnActionExecuting(filterContext);
}
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
//Execution will move here - 4
base.OnActionExecuted(filterContext);
}
}
[HandleError]
public class HomeController : Controller
{
[Filter1(Order = 1)]
[Filter2(Order = 2)]
public ActionResult Index()
{
//Execution will move here - 3
ViewData["Message"] = "Welcome to ASP.NET MVC!";
return View();
}
}
You may already aware that there are different types of filters within MVC framework. They are listed below.
Authorization filters
Action filters
Response/Result filters
Exception filters
Within each filter, you can specify the Order property. This basically describes the order of execution of the Action Filters.

Answer 2

Use TempData for getting value.
Some feature about TempData
TempData is a dictionary object that is derived from TempDataDictionary class and stored in short lives session.
TempData is used to pass data from current request to subsequent request means incase of redirection.
It’s life is very short and lies only till the target view is fully loaded.
It’s required typecasting for complex data type and check for null values to avoid error.
It is used to store only one time messages like error messages, validation messages.