Monjurul Habib

What is ViewData, ViewBag and TempData? – MVC options for passing data between current and subsequent request


ASP.NET MVC offers us three options ViewData, VieBag and TempData for passing data from controller to view and in next request. ViewData and ViewBag are almost similar and TempData performs additional responsibility. Lets discuss or get key points on those three objects:

Similarities between ViewBag & ViewData :

  1. Helps to maintain data when you move from controller to view.
  2. Used to pass data from controller to corresponding view.
  3. Short life means value becomes null when redirection occurs. This is because their goal is to provide a way to communicate between controllers and views. It’s a communication mechanism within the server call.

Difference between ViewBag & ViewData:

  1. ViewData is a dictionary of objects that is derived from ViewDataDictionary class and accessible using strings as keys.
  2. ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0.
  3. ViewData requires typecasting for complex data type and check for null values to avoid error.
  4. ViewBag doesn’t require typecasting for complex data type.

ViewBag & ViewData Example:

public ActionResult Index()
{
    ViewBag.Name = "Monjurul Habib";
    return View();
}

public ActionResult Index()
{
    ViewData["Name"] = "Monjurul Habib";
    return View();
} 

In View:

@ViewBag.Name 
@ViewData["Name"] 

TempData:

TempData is also a dictionary derived from TempDataDictionary class and stored in short lives session and it is a string key and object value. The difference is that the life cycle of the object. TempData keep the information for the time of an HTTP Request. This mean only from one page to another. This also work with a 302/303 redirection because it’s in the same HTTP Request. Helps to maintain data when you move from one controller to other controller or from one action to other action. In other words when you redirect, “Tempdata” helps to maintain data between those redirects. It internally uses session variables. Temp data use during the current and subsequent request only means it is use when you are sure that next request will be redirecting to next view. It requires typecasting for complex data type and check for null values to avoid error. generally used to store only one time messages like error messages, validation messages.

public ActionResult Index()
{
  var model = new Review()
            {
                Body = "Start",
                Rating=5
            };
    TempData["ModelName"] = model;
    return RedirectToAction("About");
}

public ActionResult About()
{
    var model= TempData["ModelName"];
    return View(model);
}

The last mechanism is the Session which work like the ViewData, like a Dictionary that take a string for key and object for value. This one is stored into the client Cookie and can be used for a much more long time. It also need more verification to never have any confidential information.

Regarding ViewData or ViewBag you should use it intelligently for application performance. Because each action goes through the whole life cycle of regular asp.net mvc request. You can use ViewData/ViewBag in your child action but be careful that you are not using it to populate the unrelated data which can pollute your controller.

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6 thoughts on “What is ViewData, ViewBag and TempData? – MVC options for passing data between current and subsequent request

  1. krystal on said:

    thou there are hundreds available on web still good effort.

    • I have made this for my own reference. I got When to use ViewBag, ViewData, or TempData. What is the difference between ViewBag, ViewData, or TempData. But i didn’t find any on the web that address all the points. Anyway, thanks for your comment :)

  2. karthick.N on said:

    I saw your post about viewbag,viewdata,tempdata. its nice. I want to do multi select and inline edit options in webgrid. is it possible ?.. Any idea send my mail.Thank you,

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  4. Amazing things here. I am very happy to peer your article.
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