ViewData, ViewBag and TempData

ViewBag

- ViewBag is used to send a small amount of data to the view.
- There may be some situation where you want to transfer some temporary data to view which is not included in the model object.
- The viewBag is a dynamic type property of ControllerBase class.
- It does not retain value when redirection occurs, It is available only for Current Request.
- ViewBag is a dynamic property and it makes use of the C# 4.0 dynamic features.

  public class DemoController : Controller
    {
        IList<Car> CarList = new List<Car>() {
                    new Car(){ CarName="i10", CarColor="Black",CarMileage=18.2 },
                    new Car(){ CarName="EON", CarColor="Silver", CarMileage=18.2 },
                    new Car(){ CarName="Swift", CarColor="Red", CarMileage=18.2},
                    new Car(){ CarName="Verna", CarColor="Black", CarMileage=18.2},
                    new Car(){ CarName="Ciaz", CarColor="Silver", CarMileage=18.2}
                };

        public ActionResult Index()
        {
            ViewBag.TotalCar = CarList.Count();
            return View();
        }
    }  
   
ViewData

- ViewData is similar to ViewBag, It can also be used to send data from controller to view.
- It is a dictionary, which possesses key-value pairs, where each key must be a string.
- Viewdata last long only for current HTTP request.

public class DemoController : Controller
    {
        public ActionResult Index()
        {
            ViewData["Simple"] = "This string is stored in viewData.";
            return View();
        }
    }
   
    To get back the value from viewData write below line in view.
   
    <h4>@ViewData["Simple"]</h4>
   
TempData

- TempData retain value across subsequent HTTP Request
- It can be used to maintain data between controller actions as well as redirects.
- It internally stores data in session but it gets destroyed earlier than a session.