Difference between Viewbag and Viewdata in ASP.NET MVC

Both are used to pass the data from controllers to views. 
The difference between Viewbag and Viewdata in ASP.NET MVC is explained below: 

View Data: 
In this, objects are accessible using strings as keys. 

Example: 

In the Controller: 
public ActionResult Index() 
{ 
var softwareDevelopers = new List<string> 
{ 
"Brendan Enrick", 
"Kevin Kuebler", 
"Todd Ropog" 
}; 
ViewData["softwareDevelopers"] = softwareDevelopers; 
return View(); 
} 

In the View: 
<ul> 
@foreach (var developer in (List<string>)ViewData["softwareDevelopers"]) 
{ 
<li> 
@developer 
</li> 
} 
</ul> 

An important note is that when we go to use out object on the view that we have to cast it since the ViewData is storing everything as object. 

View Bag: 
It will allow the objectto dynamically have the properties add to it. 

Example: 

In the Controller: 
public ActionResult Index() 
{ 
var softwareDevelopers = new List<string> 
{ 
"Brendan Enrick", 
"Kevin Kuebler", 
"Todd Ropog" 
}; 
ViewBag.softwareDevelopers = softwareDevelopers; 
return View(); 
} 

In the View: 
<ul> 
@foreach (var developer in ViewBag.softwareDevelopers) 
{ 
<li> 
@developer 
</li> 
} 
</ul> 

An important point to note is that there is no need to cast our object when using the ViewBag. This is because the dynamic we used lets us know the type.