When are Attribute instances created?

Are attributes instantiated at the same time as instances of the class to which they are applied?


Attributes are loaded when the Type.GetCustomAttributes() is called. If you just instantiate the class or even get the type, the attributes are not yet loaded.

See this example:

class Program
    static void Main()
        Console.WriteLine("Calling AttributeLoadTest.TestStatic():");
        Console.WriteLine("Loading class");
        var x = new AttributeLoadTest();
        Console.WriteLine("Loading type..");
        var t = typeof (AttributeLoadTest);
        Console.WriteLine("Calling GetCustomAttributes()");
        var ats = t.GetCustomAttributes(false);

class AttributeLoadTest
    public static void TestStatic()


class ConsoleTestAttribute : Attribute
    public ConsoleTestAttribute()
        Console.WriteLine("ConsoleTestAttribute Constructor");

This prints out:

Calling AttributeLoadTest.TestStatic():

Loading class

Loading type..

Calling GetCustomAttributes()

ConsoleTestAttribute Constructor

So calling a static method, instantiating the class, getting the type, does not instantiate the attribute. Calling GetCustomAttributes() does.

No. Attributes are bound to the type and thus instantiated when the type is loaded.

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