Object Initializer in C#

An object initializer in C# allows you to initialize an object's properties or fields at the time of object creation without explicitly calling a constructor with parameters. This feature provides a more readable and concise way to create and initialize objects.

Object initializers use curly braces {} to assign values to accessible properties or fields immediately after creating the object instance.

Syntax

Following is the basic syntax for object initializers −

ClassName objectName = new ClassName() {
    PropertyName1 = value1,
    PropertyName2 = value2,
    FieldName = value3
};

You can also omit the parentheses when using parameterless constructor −

ClassName objectName = new ClassName {
    PropertyName1 = value1,
    PropertyName2 = value2
};

Using Object Initializers with Properties

Example

using System;

public class Employee {
    public int EID { get; set; }
    public string EmpName { get; set; }
    public string EmpDept { get; set; }
}

public class Demo {
    public static void Main() {
        Employee empDetails = new Employee() {
            EID = 10,
            EmpName = "Tim",
            EmpDept = "Finance"
        };
        
        Console.WriteLine("Employee ID: " + empDetails.EID);
        Console.WriteLine("Employee Name: " + empDetails.EmpName);
        Console.WriteLine("Department: " + empDetails.EmpDept);
    }
}

The output of the above code is −

Employee ID: 10
Employee Name: Tim
Department: Finance

Using Object Initializers with Constructor Parameters

Object initializers can be combined with parameterized constructors. The constructor runs first, then the initializer sets additional properties −

Example

using System;

public class Product {
    public int ID { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
    public string Category { get; set; }
    
    public Product(int id) {
        ID = id;
        Console.WriteLine("Constructor called with ID: " + id);
    }
}

public class Program {
    public static void Main() {
        Product product = new Product(101) {
            Name = "Laptop",
            Price = 899.99m,
            Category = "Electronics"
        };
        
        Console.WriteLine($"Product: {product.Name}, Price: ${product.Price}, Category: {product.Category}");
    }
}

The output of the above code is −

Constructor called with ID: 101
Product: Laptop, Price: $899.99, Category: Electronics

Collection Initializers

Object initializers work seamlessly with collection initializers for properties that are collections −

Example

using System;
using System.Collections.Generic;

public class Department {
    public string Name { get; set; }
    public List<string> Employees { get; set; } = new List<string>();
}

public class Company {
    public string Name { get; set; }
    public List<Department> Departments { get; set; } = new List<Department>();
}

public class Program {
    public static void Main() {
        Company company = new Company {
            Name = "TechCorp",
            Departments = new List<Department> {
                new Department { Name = "IT", Employees = {"Alice", "Bob"} },
                new Department { Name = "HR", Employees = {"Carol", "Dave"} }
            }
        };
        
        Console.WriteLine("Company: " + company.Name);
        foreach(var dept in company.Departments) {
            Console.WriteLine($"Department: {dept.Name}, Employees: {string.Join(", ", dept.Employees)}");
        }
    }
}

The output of the above code is −

Company: TechCorp
Department: IT, Employees: Alice, Bob
Department: HR, Employees: Carol, Dave

Key Benefits

Conclusion

Object initializers in C# provide a clean and readable way to create and initialize objects in a single statement. They work with constructors and collections, making object creation more expressive and reducing boilerplate code while maintaining type safety and IntelliSense support.