TempData vs ViewBag vs ViewData in ASP.NET MVC

Introduction

When working with ASP.NET MVC, we often need to pass data:

From Controller to View
From one page to another
After redirect

ASP.NET MVC provides three ways to pass data:

ViewData
ViewBag
TempData

Many beginners get confused:

What is the difference?
When should I use each?
Why do we need three methods?

In this article, we will understand everything in very simple language with example and output.

Why Do We Need to Pass Data?

In MVC:

Controller handles logic
View shows data
Model stores data

If the controller has some message or data, how will it send it to the view?

That is why we use:

ViewData
ViewBag
TempData

ViewData

What is ViewData?

ViewData is a dictionary object used to pass data:

From Controller to View
Only for the current request

It works like a key-value pair.

Why Use ViewData?

We use ViewData when:

We want to send small data
Only for one page
No redirect involved

Example of ViewData

Controller

public ActionResult Index()
{
    ViewData["Message"] = "Hello from ViewData";
    return View();
}

View (Index.cshtml)

<h2>@ViewData["Message"]</h2>

Output

When you run:

https://localhost:xxxx/Home/Index

You will see:

Hello from ViewData

Important Note

If you refresh the page, data still works (same request).

But if you redirect to another action, ViewData will not work.

ViewBag

What is ViewBag?

ViewBag is a dynamic object used to pass data:

From Controller to View
Only for the current request

It is easier to use than ViewData.

Why Use ViewBag?

Cleaner syntax
No need to use key inside string
More readable

Example of ViewBag

Controller

public ActionResult Index()
{
    ViewBag.Message = "Hello from ViewBag";
    return View();
}

View

<h2>@ViewBag.Message</h2>

Output

Hello from ViewBag

ViewData vs ViewBag

Both work the same way.

Difference is:

ViewData uses dictionary
ViewBag uses dynamic object

Internally, ViewBag uses ViewData.

TempData

What is TempData?

TempData is used to pass data:

From one request to another
Mainly used after Redirect

It stores data temporarily.

Why Use TempData?

We use TempData when:

We redirect to another action
We want to show success message after form submit
We need data for next request

Example of TempData

Controller

public ActionResult Index()
{
    TempData["Message"] = "Data saved successfully!";
    return RedirectToAction("About");
}

public ActionResult About()
{
    return View();
}

About View

<h2>@TempData["Message"]</h2>

Output

Data saved successfully!

Important

TempData works only once.

After reading it, data is removed automatically.

Comparison Table (Easy to Understand)

Feature	ViewData	ViewBag	TempData
Type	Dictionary	Dynamic	Dictionary
Scope	Current request	Current request	Next request
Used For	Controller → View	Controller → View	Redirect
Lifetime	Until request ends	Until request ends	Until read

Real-Life Example (Very Easy)

Imagine a teacher giving homework.

ViewData → Teacher tells message in class (same period only)
ViewBag → Same as above but easier way
TempData → Teacher gives note to student to show parents at home (next request)

When Should You Use What?

Use ViewData when:

Passing small data
Current page only

Use ViewBag when:

Simple data
Cleaner code
Beginner-friendly

Use TempData when:

Redirecting to another action
Showing success message after form submit

Conclusion

In this article, we learned:

What is ViewData
What is ViewBag
What is TempData
Why we use them
When to use them
Example with output
Real-life explanation