C# Structures Tutorial with Examples

What is Struct?
Struct vs Class
Constructor of Struct
Methods and properties of struct
Indexers and Events of Struct

1. What is Struct?

In C#, Struct (structure) is a special type of value, it creates a variable, to store multiple values, but the values are related to each other.

For example, information about an employee include:

Employee number
Employee name
Position

You can create 3 variables to store the information above of employee. However you can create a Struct to store all three information on in a single variable.

C # uses struct keyword to declare a Struct.

Employee.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    struct Employee
    {
        public string empNumber;
        public string empName;
        public string position;
        public Employee(string empNumber, string empName, string position)
        {
            this.empNumber = empNumber;
            this.empName = empName;
            this.position = position;
        }
    }
}

For example, use Struct:

EmployeeTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    class EmployeeTest
    {
        public static void Main(string[] args)
        {
            Employee john = new Employee("E01","John", "CLERK");
            Console.WriteLine("Emp Number: " + john.empNumber);
            Console.WriteLine("Emp Name: " + john.empName);
            Console.WriteLine("Emp Position: " + john.position);
            Console.Read();
        }
    }
}

Running the example:

Emp Number: E01
Emp Name: John
Emp Position: CLECK

2. Struct vs Class

Struct is commonly used to create an object to store the value, while the class is using more diversely.

Struct does not allow inherit, it can not expand from a certain class or a struct.
Struct does not allow implement Interface.

One of the struct frequently used in C# that is DateTime, a struct describing the date and time. You can see more about using date and time in C# at:
CSharp Date Time

If struct appears as a parameter in a method, it is passed as a value. Meanwhile, if the class appears as a parameter in a method it is passed as a reference.

MyClass.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    class MyClass
    {
       public string name = "Abc";
       public MyClass(string name)
       {
           this.name = name;
       }
    }
}

MyStruct.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    struct MyStruct
    {
       public string name;

       public MyStruct(string name)
       {
           this.name = name;
       }
    }
}

MyTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    class MyTest
    {
        private static void passToMe(MyClass myClass, MyStruct myStruct)
        {
            // Change value for name field.
            myClass.name = "New Name";
 
            // Change value for name field.
            myStruct.name = "New Name";
        } 
        public static void Main(string[] args)  
        {
            MyClass myClass = new MyClass("Abc");
            MyStruct myStruct = new MyStruct("Abc");

            Console.WriteLine("Before pass to method");
            Console.WriteLine("myClass.name = " + myClass.name);// Abc
            Console.WriteLine("myStruct.name = " + myStruct.name);// Abc 
            Console.WriteLine("Pass to method");

            // 'myStruct' passed to the method is a copy.
            // (Not the original object).
            passToMe(myClass, myStruct); 
            Console.WriteLine("myClass.name = " + myClass.name); // New Name
            Console.WriteLine("myStruct.name = " + myStruct.name);// Abc 
            Console.Read(); 
        } 
    } 
}

Running the example:

Before pass to method
myClass.name = Abc
myStruct.name = Abc
Pass to method
myClass.name = New Name
myStruct.name = Abc

3. Constructor of Struct

Struct can have Constructors but do not have Destructor

Here are few notes for the Constructor:

You can not write a default constructor (no parameters) for struct.
In the constructor you must assign values to all fields that don't have value.

4. Methods and properties of struct

Struct can have methods and properties, and because Struct do not inherit, therefore, all its modes and properties are not allowed to be abstract.

Book.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpStructureTutorial
{
    struct Book
    {
        private string title;
        private string author;

        // Property
        public string Title
        {
            get
            {
                return this.title;
            }
            set
            {
                this.title = value;
            }
        }
        // Property
        public string Author
        {
            get
            {
                return this.author;
            }
        }
        // Constructor.
        public Book(string title, string author)
        {
            this.title = title;
            this.author = author;
        }
        // Method.
        public string GetInfo()
        {
            return "Book Title: " + this.title + ", Author: " + this.author;
        }
    }
}

5. Indexers and Events of Struct

Struct can have Indexer and Event, see more about Indexer and Event at:

CSharp Delegate, Event