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home / developersection / forums / how to create a custom attribute in c#?
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How to create a custom attribute in C#?

Ashutosh Patel 583 30 Oct 2025

Explain about creating a custom attribute in C#, and also how to use it with a class, a method, and a property? 

c# c#Programming Basics
Updated 04 Nov 2025
Ashutosh Patel
Ashutosh Patel

Web Developer

I am a professional .NET developer with over 4 years of hands-on industry experience in designing, developing, and maintaining scalable web applications. I specialize in .NET Core, C#, RESTful APIs, and database-driven systems using SQL Server.

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1 Answers

Amrith Chandran
Amrith Chandran 03 Nov 2025
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In C#, you can create your own custom attributes, which are pieces of metadata associated with your code elements: classes, methods, properties, etc., that can later be read through reflection.
Let's see the step-by-step guide to create a custom attribute in C#.

Create a Custom Attribute Class
A custom attribute is simply a class that derives from System.Attribute namespace.

using System;
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method | AttributeTargets.Property, AllowMultiple = false)]
public class AuthorAttribute : Attribute
{
   public string UserName { get; }
   public string Version { get; set; }
   public AuthorAttribute(string name)
   {
       UserName = name;
       Version = "1.0";
   }
}

Note: AttributeTargets.Class is allowed to use this attribute with the classes, AttributeTargets.Method is allowed to use with methods and   AttributeTargets.Property allows to use of properties. You can also allow this attribute to be used only with the call by setting the AttributeTargets.Class.

You can also allow multiple uses with AllowMultiple = true.

Apply the Attribute

Now you can use this attribute to decorate your class, method, or property:

[Author("Manish Sharma", Version = "2.3")]
public class ClassName
{
   [Author("Pooja Verma")]
   public void MethodName()
   {
       Console.WriteLine("Hello C# developer");
   }
}

Retrieve the Attribute via Reflection

You can read attribute data at runtime like given below:

using System;
using System.Reflection;
class Program
{
   static void Main()
   {
       Type type = typeof(ClassName);
       // Get class attribute
       var classAttr = (AuthorAttribute)Attribute.GetCustomAttribute(type, typeof(AuthorAttribute));
       Console.WriteLine($"Class Author: {classAttr.UserName}, Version: {classAttr.Version}");
       // Get method attribute
       MethodInfo method = type.GetMethod("MethodName");
       var methodAttr = (AuthorAttribute)Attribute.GetCustomAttribute(method, typeof(AuthorAttribute));
       Console.WriteLine($"Method Author: {methodAttr.UserName}, Version: {methodAttr.Version}");
   }
}

Output

Class Author: Manish Sharma, Version: 2.3
Method Author: John Doe, Version: 1.0

Would you learn about:  What is the difference between throw and throw ex?

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