implementing a rating system with stars and reviews in an MVC C# application involves several steps. Here's a basic outline of how you could approach it:

1. Database Setup: You need a database table to store product information, including the average rating, and another table to store individual ratings and reviews for each product.

2. Model: Create models for your products and ratings. Your product model should include properties for the product name, description, and average rating. Your rating model should include properties for the rating value, review comment, and a foreign key linking it to the corresponding product.

3. Controller: Create controllers to handle CRUD (Create, Read, Update, Delete) operations for both products and ratings. Your controllers should have methods to calculate the average rating for a product and to retrieve ratings and reviews for a given product.

4. View: Create views to display products, including their average rating and reviews. You'll need a way for users to submit ratings and reviews as well.

5. Business Logic: Implement logic in your controllers to calculate the average rating for each product based on the ratings submitted by users. This could be done by querying the ratings for each product and calculating the average.

6. User Interface: In your view, display the average rating for each product along with the stars representing the rating. Allow users to submit ratings and reviews through a form.

Here's a simplified example of what some of your code might look like:

Product Model:

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public double AverageRating { get; set; }
    // Other properties
    
    // Navigation property for ratings
    public virtual ICollection Ratings { get; set; }
}

Rating Model:

public class Rating
{
    public int Id { get; set; }
    public int ProductId { get; set; }
    public int Value { get; set; }
    public string Review { get; set; }
    // Other properties
    
    // Navigation property for product
    public virtual Product Product { get; set; }
}

Controller:

public class ProductController : Controller
{
    private readonly ApplicationDbContext _context;

    public ProductController(ApplicationDbContext context)
    {
        _context = context;
    }

    // Action to calculate and display average rating for a product
    public IActionResult Details(int id)
    {
        var product = _context.Products.Include(p => p.Ratings).FirstOrDefault(p => p.Id == id);
        if (product == null)
        {
            return NotFound();
        }
        
        product.AverageRating = product.Ratings.Any() ? product.Ratings.Average(r => r.Value) : 0;

        return View(product);
    }

    // Other actions for CRUD operations
}

View (Details.cshtml):

@model Product

@Model.Name
@Model.Description
Average Rating: @Model.AverageRating


@for (int i = 0; i < Model.AverageRating; i++)
{
    
}

This is a basic example to get you started. You would need to expand upon this with error handling, input validation, user authentication, and more depending on your specific requirements.