LINQ with custom objects in C Sharp (C#) - Mini Project: Build & Apply

LINQ with custom objects

📖 Scenario: You work in a bookstore and want to organize a list of books by their price. Each book has a title and a price.

🎯 Goal: You will create a list of book objects, set a price limit, use LINQ to find books cheaper than that limit, and then print their titles.

📋 What You'll Learn

Create a Book class with Title and Price properties

Create a list of Book objects with exact titles and prices

Create a priceLimit variable to filter books

Use LINQ query with where to select books cheaper than priceLimit

Print the titles of the filtered books

💡 Why This Matters

🌍 Real World

Filtering and selecting items from a list of custom objects is common in apps like online stores, libraries, or inventory systems.

💼 Career

Understanding LINQ with custom objects helps you write clean, readable code to query data collections efficiently in many C# jobs.

1

Create the Book class and list of books

Create a Book class with Title and Price properties. Then create a list called books with these exact entries: "C# Basics" priced 30, "LINQ in Action" priced 45, "ASP.NET Core" priced 50, "Entity Framework" priced 40.

C Sharp (C#)

// Define Book class and create list books with given entries
// Your code here

Need a hint?

Define a class with two properties. Then create a list and add new Book objects with the exact titles and prices.

2

Set the price limit

Inside the Main method, create an integer variable called priceLimit and set it to 45.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Book
{
    public string Title { get; set; }
    public int Price { get; set; }
}

class Program
{
    static void Main()
    {
        List books = new List
        {
            new Book { Title = "C# Basics", Price = 30 },
            new Book { Title = "LINQ in Action", Price = 45 },
            new Book { Title = "ASP.NET Core", Price = 50 },
            new Book { Title = "Entity Framework", Price = 40 }
        };
        // Create priceLimit variable and set to 45
        // Your code here
    }
}

Need a hint?

Just create an integer variable named priceLimit and assign it the value 45.

3

Use LINQ to find books cheaper than priceLimit

Use a LINQ query with var cheapBooks = from book in books where book.Price < priceLimit select book; inside the Main method, after defining priceLimit.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Book
{
    public string Title { get; set; }
    public int Price { get; set; }
}

class Program
{
    static void Main()
    {
        List books = new List
        {
            new Book { Title = "C# Basics", Price = 30 },
            new Book { Title = "LINQ in Action", Price = 45 },
            new Book { Title = "ASP.NET Core", Price = 50 },
            new Book { Title = "Entity Framework", Price = 40 }
        };
        int priceLimit = 45;
        // Use LINQ query to find books cheaper than priceLimit
        // Your code here
    }
}

Need a hint?

Use a LINQ query expression with from, where, and select to filter books cheaper than priceLimit.

4

Print the titles of the filtered books

Use a foreach loop to print the Title of each book in cheapBooks.

C Sharp (C#)

using System;
using System.Collections.Generic;
using System.Linq;

class Book
{
    public string Title { get; set; }
    public int Price { get; set; }
}

class Program
{
    static void Main()
    {
        List books = new List
        {
            new Book { Title = "C# Basics", Price = 30 },
            new Book { Title = "LINQ in Action", Price = 45 },
            new Book { Title = "ASP.NET Core", Price = 50 },
            new Book { Title = "Entity Framework", Price = 40 }
        };
        int priceLimit = 45;
        var cheapBooks = from book in books
                         where book.Price < priceLimit
                         select book;
        // Print titles of cheapBooks
        // Your code here
    }
}

Need a hint?

Use a foreach loop to go through cheapBooks and print each book's Title with Console.WriteLine.