Passing Data using ViewBag in .NET Core (Beginner Guide)
👋 Introduction
If you are just starting with ASP.NET Core MVC, you might wonder:
“How do I send data from my controller to my view?”
Don’t worry 😊
Passing Data using ViewBag in .NET Core is one of the simplest and beginner-friendly ways to do this.
It is quick, flexible, and very easy to understand.
So, let’s learn it step by step, with clear examples, real-life scenarios, and friendly explanations ✨
📚 What you are going to learn in this lesson
✔️ What ViewBag is and why it exists
✔️ How Passing Data using ViewBag in .NET Core works
✔️ How to send simple data (text, numbers) to a View
✔️ How to send multiple values using ViewBag
✔️ A real-world example you can relate to
✔️ Common beginner mistakes (and how to avoid them)
🧠 Easy real-world idea first
Think of ViewBag like a small temporary bag 🎒
The controller puts data inside it,
and the View opens the bag and reads the data.
Simple, right? 😄
🧩 What is ViewBag?
ViewBag is a dynamic object used in ASP.NET Core MVC.
It helps in Passing Data using ViewBag in .NET Core from a Controller to a View.
✔️ It does not require a model
✔️ It works only for the current request
✔️ It is very useful for small data
🧪 Example 1: Passing simple text using ViewBag in .NET Core
📌 Controller Code
public class HomeController : Controller
{
public IActionResult Index()
{
ViewBag.Message = "Welcome to ASP.NET Core!";
return View();
}
}
📌 View Code (Index.cshtml)
<h2>@ViewBag.Message</h2>
✅ Output
Welcome to ASP.NET Core!
🧠 Explanation
- The controller stores a message inside
ViewBag.Message - The view reads it using
@ViewBag.Message - So, Passing Data using ViewBag in .NET Core becomes very easy 👍
🧪 Example 2: Passing multiple values using ViewBag in .NET Core
📌 Controller Code
public IActionResult About()
{
ViewBag.Name = "Prashant";
ViewBag.Age = 42;
ViewBag.City = "Bhagalpur";
return View();
}
📌 View Code
<p>Name: @ViewBag.Name</p>
<p>Age: @ViewBag.Age</p>
<p>City: @ViewBag.City</p>
✅ Output
Name: Prashant
Age: 42
City: Bhagalpur
🧠 Explanation
Here, multiple values are stored inside ViewBag.
Because ViewBag is dynamic, you can add any property anytime.
So, Passing Data using ViewBag in .NET Core stays flexible and fast 🚀
🧪 Example 3: Passing numbers and doing calculation
📌 Controller Code
public IActionResult Result()
{
ViewBag.Total = 80;
ViewBag.Obtained = 65;
return View();
}
📌 View Code
<p>Total Marks: @ViewBag.Total</p>
<p>Obtained Marks: @ViewBag.Obtained</p>
<p>Percentage: @(ViewBag.Obtained * 100 / ViewBag.Total)%</p>
✅ Output
Total Marks: 80
Obtained Marks: 65
Percentage: 81%
🧠 Explanation
You can even perform calculations in the View.
However, keep logic minimal in Views for clean code ✔️
🌍 Real-life Scenario: Showing error or success message
Imagine a form submission fails ❌
You want to show a quick error message without creating a full model.
📌 Controller
ViewBag.Error = "Something went wrong. Please try again.";
📌 View
@if(ViewBag.Error != null)
{
<div style="color:red">@ViewBag.Error</div>
}
💡 Why ViewBag is useful here?
- You don’t need a model
- You can quickly pass messages
- Perfect for alerts, warnings, and notifications
That’s why Passing Data using ViewBag in .NET Core is very handy in real apps 👍
⚠️ Common beginner mistakes
❌ Using ViewBag for large or complex data
❌ Expecting ViewBag to work across multiple requests
❌ Misspelling property names (no compile-time check)
✔️ Tip: For large data, always use Models or ViewModel
✨ Quick Summary
- ViewBag is simple and dynamic
- It is best for small data
- It works between Controller and View only
- Passing Data using ViewBag in .NET Core is perfect for beginners
You’re doing great so far 👏 Keep going!
👉 Next what?
In the next chapter you will learn “Passing Data using ViewBag in .net core” 🚀
Until then, practice these examples and try modifying the values yourself.
If you want, ask me for ViewData vs ViewBag or Model vs ViewBag next 😊
