What is the difference between TempData, ViewData, and ViewBag?

Question

ICSM Computer · Answer

In ASP.NET MVC, TempData, ViewData, and ViewBag are used to
pass data from controllers to views, but they differ in 
lifetime, usage, and behavior.
Quick Comparison Table
Feature
ViewData
ViewBag
TempData
Type
Dictionaryandlt;string, objectandgt;
Dynamic (wraps ViewData)
TempDataDictionary (string keys)
Lifetime
Current request only
Current request only
Survives redirect (one request)
Purpose
Pass data to view
Same as ViewData, more concise
Pass data across requests (e.g. after redirect)
Syntax
ViewData["Name"]
ViewBag.Name
TempData["Name"]
Null safety
Prone to key typos
Prone to runtime errors
Same
Use case
Any type of view data
Simpler syntax for view data
One-time messages, redirects
Detailed Breakdown
ViewData
Dictionary-like object (ViewDataDictionary)Available only during the current HTTP requestRequires type casting and string keys
// Controller
ViewData["Message"] = "Hello from ViewData";
// View
andlt;h2andgt;@ViewData["Message"]andlt;/h2andgt;
ViewBag
Syntactic sugar over ViewData using dynamicCleaner and avoids casting, but less safe at compile timeAlso available only during the current request
// Controller
ViewBag.Message = "Hello from ViewBag";
// View
andlt;h2andgt;@ViewBag.Messageandlt;/h2andgt;
TempData
Stores data until it is read (or next request ends)Survives a redirect (RedirectToAction)Backed by Session — so session must be enabled
// Controller
TempData["SuccessMessage"] = "Profile updated successfully";
return RedirectToAction("Index");
// In redirected view
@if (TempData["SuccessMessage"] != null)
{
    andlt;divandgt;@TempData["SuccessMessage"]andlt;/divandgt;
}
When to Use What?
Scenario
Use
Pass data to view within same request
ViewBag or ViewData
Share data between controller and view
ViewBag or ViewData
Pass one-time messages (after redirect)
TempData
Maintain small data across requests
TempData
Store model or large objects
Use ViewModel instead
Tip: Reuse ViewBag/ViewData with Partial Views
Both ViewBag and ViewData are passed automatically to partial views:
@Html.Partial("_MyPartial", model) // gets the ViewData and ViewBag
Pitfalls
ViewBag/ViewData are not type-safe – you can mistype the key or use wrong casting.TempData gets cleared after one request unless you use 
TempData.Keep().

interview

What is the difference between TempData, ViewData, and ViewBag?

ICSM Computer

Can you answer this question?

1 Answers

Quick Comparison Table

Detailed Breakdown

`ViewData`

`ViewBag`

`TempData`

When to Use What?

Tip: Reuse ViewBag/ViewData with Partial Views

Pitfalls

Liked By

Feature	`ViewData`	`ViewBag`	`TempData`
Type	`Dictionary<string, object>`	Dynamic (wraps `ViewData`)	`TempDataDictionary` (`string` keys)
Lifetime	Current request only	Current request only	Survives redirect (one request)
Purpose	Pass data to view	Same as `ViewData`, more concise	Pass data across requests (e.g. after redirect)
Syntax	`ViewData["Name"]`	`ViewBag.Name`	`TempData["Name"]`
Null safety	Prone to key typos	Prone to runtime errors	Same
Use case	Any type of view data	Simpler syntax for view data	One-time messages, redirects

Scenario	Use
Pass data to view within same request	`ViewBag` or `ViewData`
Share data between controller and view	`ViewBag` or `ViewData`
Pass one-time messages (after redirect)	`TempData`
Maintain small data across requests	`TempData`
Store model or large objects	Use `ViewModel` instead