Data Passing: ViewData, ViewBag, and the ViewModel Revolution

ViewData: The Fast Dictionary

ViewData is a dictionary of objects that is derived from the ViewDataDictionary class. It uses string keys to store data.

// In Controller
ViewData["Greeting"] = "Hello Specialist!";
// In View
<h1>@ViewData["Greeting"]</h1>
                        

ViewBag: The Dynamic Wrapper

ViewBag is a dynamic property that is essentially a wrapper around ViewData. It allows you to use property-like syntax.

// In Controller
ViewBag.Greeting = "Hello Architect!";
// In View
<h1>@ViewBag.Greeting</h1>
                        

The "Expert" Verdict: Stop Using Both!

If you have more than 3 years of experience, you should almost NEVER use ViewData or ViewBag. Why? Because they are **Weakly Typed**. You get zero IntelliSense and zero compile-time error checking. One typo in a string key like ViewData["Greetng"] and your site crashes in production.

The ViewModel Pattern (12-Year Standard)

Always create a dedicated class for your view. This ensures 100% type safety and makes your views extremely clean.

public class UserDashboardViewModel {
    public string UserName { get; set; }
    public List RecentOrders { get; set; }
}