What Is ViewBag In ASP.Net MVC

Passing Data From A Controller To A View In ASP.Net MVC

In an ASP.NET MVC application, a controller typically performs the business logic of the application and needs to return the result to the user through a view.

You can use the following objects to pass data between controller and view:

1. ViewData
2. ViewBag
3. TempData

What Is ViewBag ?

• ViewBag is also used to transfer data from a controller to a view.
• ViewBag exists only for the current request and becomes null if the request is redirected.
• ViewBag is a dynamic property based on the dynamic features introduced in C# 4.0.
• ViewBag does not require typecasting when you use complex data type.

The general syntax of ViewBag is as follows:

ViewBag.<PropertyName> = <Value>;

where,

• Property: Is a String value that represents a property of ViewBag.
• Value: Is the value of the property of ViewBag, Value may be a String, object, list, array or a different type, such as int, char, float, double DateTime etc.

Note: ViewBag does not provide compile time error checking. For Example- if you mis-spell keys you wouldn’t get any compile time errors. You get to know about the error only at runtime.

Note: ViewData and ViewBag can access each other data interchangeably.

Source Code Of HomeController

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using ViewBagDemo.Models;

namespace ViewBagDemo.Controllers
{
    public class HomeController : Controller
    {
        // GET: Home
        public ActionResult Index()
        {
            ViewBag.Message = "Message from View Bag !!";
            ViewBag.CurrentDate = DateTime.Now.ToLongDateString();

            string[] fruits = { "Apple", "Banana", "Grapes", "Orange" };

            ViewBag.FruitsArray = fruits;

            ViewBag.SportsList = new List<string>()
            {
                "Cricket",
                "Football",
                "Hockey",
                "Baseball"
            };

            Employee Anas = new Employee();

            Anas.EmpId = 22;
            Anas.EmpName = "Anas Qureshi";
            Anas.EmpDesignation = "Manager";

            ViewBag.Employee = Anas;

            ViewData["CommonMessage"] = "This message is accessible by both ViewBag and ViewData";

            int[] MyArray = {10,20,30,40 };
            ViewBag.Nums = MyArray;

            return View();
        }
    }
}

Source Code Of Index.cshtml (View)

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>

<h2>@ViewBag.Message</h2>
<h2>@ViewBag.CurrentDate</h2>

<ul>
    @{
        foreach (string i in ViewBag.FruitsArray)
        {
            <li>@i</li>
        }
    }
</ul>

<ul>
    @{
        foreach (int i in ViewBag.Nums)
        {
            <li>@i</li>
        }
    }
</ul>

<ul>
    @{
        foreach (string i in ViewBag.SportsList)
        {
            <li>@i</li>
        }
    }
</ul>

@{ 
    var a = ViewBag.Employee;
}

<p>@a.EmpId</p>
<p>@a.EmpName</p>
<p>@a.EmpDesignation</p>

<h2>Data comes from ViewData = @ViewData["CommonMessage"]</h2>
<h2>Data comes from ViewBag = @ViewBag.CommonMessage</h2>