project for cart to add items

This is also in asp.net web forms

https://code.tutsplus.com/build-a-shopping-cart-in-aspnet--net-1663t

No, this is clearly in asp.net c# please again look closely 

https://learn.microsoft.com/en-us/aspnet/web-forms/overview/getting-started/getting-started-with-aspnet-45-web-forms/shopping-cart

you might be mistaken because they have created separate BLL (Business Logic Layer) class.

actually this was in MVC

The above example was in c# asp.net web app, if you want c# windows form then go through this

https://bitsandbinaries.wordpress.com/net-programming/windows-forms/a-shopping-cart-program-in-c-windows-forms/

In C# or vb.net

This is an example by microsoft of an add to cart for an old asp.net webform project as you mentioned

https://learn.microsoft.com/en-us/aspnet/web-forms/overview/getting-started/getting-started-with-aspnet-45-web-forms/shopping-cart

in asp.net c# or vb.net with example

Sure! I can provide you with a simple Dot Net project that allows users to add items to a cart and proceed with further actions. Here's a step-by-step guide on how to create the project:

1. Open Visual Studio and create a new ASP.NET Web Application project.
2. Choose the "Empty" template and make sure to select the "MVC" checkbox.
3. Once the project is created, right-click on the "Controllers" folder and add a new controller called "CartController".
4. In the "CartController", create an action method called "AddToCart" that takes the item details as parameters.
5. Inside the "AddToCart" method, you can implement the logic to add the item to the cart. You can use a session variable or a database to store the cart items.
6. Next, create a view for the "AddToCart" action method. This view will display the item details and provide a form to add the item to the cart.
7. In the view, use HTML form elements to capture the item details and submit the form to the "AddToCart" action method.
8. Finally, you can add additional actions and views to handle further actions such as updating the cart, removing items from the cart, and proceeding to checkout.

This is a basic outline of how you can create a Dot Net project for adding items to a cart. You can customize and enhance the project based on your specific requirements. Remember to handle validation, authentication, and any other necessary features to make the project robust and secure.