How to Create List of Objects in C# Easily

In C#, you create a list of objects using the List<T> class where T is your object type. First, define a class for your objects, then create a List<YourClass> and add instances to it.

Syntax

To create a list of objects in C#, you use the generic List<T> class from System.Collections.Generic. Replace T with your class name. You can then add objects to this list.

• List<YourClass> listName = new List<YourClass>(); creates an empty list.
• listName.Add(objectInstance); adds an object to the list.

csharp

using System.Collections.Generic;

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

// Create a list of Person objects
List<Person> people = new List<Person>();

// Add a new Person to the list
people.Add(new Person { Name = "Alice", Age = 30 });

Example

This example shows how to define a Person class, create a list of Person objects, add multiple people, and print their details.

csharp

using System;
using System.Collections.Generic;

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public class Program
{
    public static void Main()
    {
        List<Person> people = new List<Person>();

        people.Add(new Person { Name = "Alice", Age = 30 });
        people.Add(new Person { Name = "Bob", Age = 25 });
        people.Add(new Person { Name = "Charlie", Age = 35 });

        foreach (var person in people)
        {
            Console.WriteLine($"Name: {person.Name}, Age: {person.Age}");
        }
    }
}

Output

Name: Alice, Age: 30
Name: Bob, Age: 25
Name: Charlie, Age: 35

Common Pitfalls

Common mistakes when creating lists of objects include:

• Forgetting to include using System.Collections.Generic; which is needed for List<T>.
• Trying to add objects of the wrong type to the list.
• Not initializing the list before adding objects, causing a NullReferenceException.

Always initialize your list with new List<T>() before adding items.

csharp

using System.Collections.Generic;

public class Car
{
    public string Model { get; set; }
}

// Wrong: list not initialized
List<Car> cars;
cars = new List<Car>(); // Added initialization to fix error
cars.Add(new Car { Model = "Tesla" }); // This works now

// Right: list initialized
List<Car> cars2 = new List<Car>();
cars2.Add(new Car { Model = "Tesla" }); // Works fine

Quick Reference

Summary tips for creating and using lists of objects in C#:

• Use List<T> from System.Collections.Generic.
• Initialize the list before adding objects.
• Add objects using Add() method.
• Use foreach to loop through the list.

Key Takeaways

Use List to create a list of objects where T is your class type.

Always initialize your list with new List() before adding objects.

Add objects to the list using the Add() method.

Use foreach loops to access each object in the list easily.

Include using System.Collections.Generic to use List.