ViewData and ViewBag allows you to access any
data in view that was passed from controller.
The main difference between those two is the way you
are accessing the data.
In ViewBag you are accessing data using string as keys - ViewBag[“numbers”]
In ViewData you are accessing data using properties - ViewData.numbers.
In ViewBag you are accessing data using string as keys - ViewBag[“numbers”]
In ViewData you are accessing data using properties - ViewData.numbers.
ViewData example
CONTROLLER
CONTROLLER
var Numbers = new List<int> {
1, 2, 3 };
ViewData["numbers"] =
Numbers;
VIEW
<ul>
@foreach
(var number in
(List<int>)ViewData["numbers"])
{
<li>@number</li>
}
</ul>
ViewBag example
CONTROLLER
CONTROLLER
var Numbers = new List<int> {
1, 2, 3 };
ViewBag.numbers = Numbers;
VIEW
<ul>
@foreach
(var number in
ViewBag.numbers)
{
<li>@number</li>
}
</ul>
Session is another very useful object that will hold
any information.
For instance when user logged in to the system you want to hold his authorization level.
// GetUserAuthorizationLevel - some method that returns int value for user authorization level.
For instance when user logged in to the system you want to hold his authorization level.
// GetUserAuthorizationLevel - some method that returns int value for user authorization level.
Session["AuthorizationLevel"]
= GetUserAuthorizationLevel(userID);
This information will be
stored in Session as long as user session is active.
This can be changed in Web.config file:
This can be changed in Web.config file:
<system.web>
<sessionState mode="InProc" timeout="30"/>
So then in controller
inside the action :
public ActionResult
LevelAccess()
{
if (Session["AuthorizationLevel"].Equals(1))
{
return View("Level1");
}
if (Session["AuthorizationLevel"].Equals(2))
{
return View("Level2");
}
return View("AccessDenied");
}
TempData is very similar to ViewData and ViewBag
however it will contain data only for one request.
CONTROLLER
// You created a method to add new client.
TempData["ClientAdded"] = "Client has been added";
CONTROLLER
// You created a method to add new client.
TempData["ClientAdded"] = "Client has been added";
VIEW
@if(TempData["ClientAdded"] != null)
{
<h3>@TempData["ClientAdded"]
</h3>
}
TempData is useful when you want to pass some information from View to Controller. For instance you want to hold time when view was requested.
VIEW
@{
TempData["DateOfViewWasAccessed"]
= DateTime.Now;
}
CONTROLLER
if (TempData["DateOfViewWasAccessed"]!= null)
{
DateTime time = DateTime.Parse(TempData["DateOfViewWasAccessed"].ToString());
}
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