C# Error CS0653 – Cannot apply attribute class ‘{0}’ because it is abstract

C# Error

CS0653 – Cannot apply attribute class ‘{0}’ because it is abstract

Reason for the Error & Solution

Cannot apply attribute class ‘class’ because it is abstract

An custom attribute class cannot be used as an attribute.

The following sample generates CS0653:

// CS0653.cs  
using System;  
  
public abstract class MyAttribute : Attribute  
{  
}  
  
public class My2Attribute : MyAttribute  
{  
}  
  
[My]   // CS0653  
// try the following line instead  
// [My2]  
class MyClass  
{  
   public static void Main()  
   {  
   }  
}