#viewbag

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ViewBag and ViewData In Asp.Net MVC

In this article we will under stand How to Pass Data From Controller to View by Sagar Jaybhay.

How to Pass Data From Controller to View using ViewBag and ViewData?

ViewBag and ViewData In Asp.Net MVC

Both are used to pass data from controller to view.

ViewData is a dictionary of objects which store and retrieve the data based on key.

ViewData["Today"] = DateTime.Now;

See the above code.

https://youtu.be/7mZ89MvGnzU

ViewBag uses the dynamic keyword internally and the dynamic keyword is introduced in C# v4. It allows objects to add as properties.

ViewBag.list = list;

See the above code.

In this, both do not provide compile-time error checking. Means if given ABC as a key name in the controller and in view if you misspell Abc then it will not provide compile-time checking. You will get the error at runtime only. It is good practice to pass data from controller to view using a strongly typed model.

ViewBag is a sugar coating over ViewData. Internally ViewBag properties are stored name-value pair list.

State Management in ASP.NET MVC

In ASP .NET MVC, ViewData, View Bag, TempData is used to maintain the state in our page/view.Viewdata, ViewBag is used to transfer date/information from controller to view in the current request. TempData use to transfer data from controller to another controller. It has capable of maintaining the data to not only on current request, it can maintain the data in next HTTP requests. Flow Diagram :…

How to: What's the difference between ViewData and ViewBag?

What’s the difference between ViewData and ViewBag?

I saw the ViewBag in MVC 3. How’s that different than ViewData in MVC 2?

Answer: What’s the difference between ViewData and ViewBag?

It uses the C# 4.0 dynamic feature. It achieves the same goal as viewdata and should be avoided in favor of using strongly typed view models (the same way as viewdata should be avoided).

So basically it replaces

                 Figure: - difference between tempdata, viewdata and viewbag

Temp data: - 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.

View data: - Helps to maintain data when you move from controller to view.

View Bag: - It’s a dynamic wrapper around view data. When you use “Viewbag” type casting is not required. It uses the dynamic keyword internally.

                                                                                                                 Figure: - dynamic keyword

Session variables: - By using session variables we can maintain data from any entity to any entity.

Hidden fields and HTML controls: - Helps to maintain data from UI to controller only. So you can send data from HTML controls or hidden fields to the controller using POST or GET HTTP methods.

Below is a summary table which shows different mechanism of persistence.