C# Anonymous Types: Creating Objects Without Explicit Class Definitions

Learn how to use anonymous types in C# for creating objects without defining a separate class. This tutorial explains their syntax, demonstrates their use for grouping data, and highlights scenarios where anonymous types offer a concise and efficient alternative to explicitly defining classes.

Understanding and Using Anonymous Types in C#

Introduction

C# anonymous types provide a convenient way to create objects without explicitly defining a class. These types are implicitly defined by the compiler, and their properties are read-only. They're especially useful for temporary objects or when you need a simple way to group data.

Creating Anonymous Types

Anonymous types are created using the new operator with an object initializer. The compiler automatically generates a unique type name.

Example 1: Basic Anonymous Type

This example shows how to create a simple anonymous type representing a student and access its properties.

using System;

namespace CSharpFeatures {
    class AnonymousTypesExample {
        public static void Main() {
            // Creating Anonymous Object
            var student = new { ID = 101, Name = "Peter", Email = "peter@example.com" };

            // Accessing object properties
            Console.WriteLine(student.ID);
            Console.WriteLine(student.Name);
            Console.WriteLine(student.Email);
        }
    }
}

101
Peter
peter@example.com
        

Explanation Example 1

The var keyword lets the compiler infer the type. The properties ID, Name, and Email are created directly within the object initializer.

Example 2: Anonymous Types in LINQ Queries

Anonymous types are frequently used with LINQ to select specific properties from a data source without creating a new class.

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

namespace CSharpFeatures {
    class Student {
        public int ID { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
    }

    class AnonymousTypesExample {
        public static void Main() {
            List<Student> students = new List<Student> {
                new Student { ID = 101, Name = "Rahul", Email = "rahul@example.com" },
                new Student { ID = 102, Name = "Peter", Email = "peter@abc.com" },
                new Student { ID = 103, Name = "Irfan", Email = "irfan@example.com" }
            };

            var stquery =
                from student in students
                select new { student.ID, student.Name, student.Email }; // Creating Anonymous Types

            foreach (var st in stquery) {
                Console.WriteLine("ID = {0}, Name = {1}, Email = {2}", st.ID, st.Name, st.Email);
            }
        }
    }
}

ID = 101, Name = Rahul, Email = rahul@example.com
ID = 102, Name = Peter, Email = peter@abc.com
ID = 103, Name = Irfan, Email = irfan@example.com
        

Explanation Example 2

This LINQ query selects specific properties from the Student objects and creates a new anonymous type for each selected record.

Conclusion

Anonymous types offer a concise way to create simple, temporary objects in C#. Their use in LINQ queries simplifies selecting specific data without needing to define separate classes.