C# Extension Method for Object

Question

Is it a good idea to use an extension method on the Object class?

I was wondering if by registering this method if you were incurring a performance penalty as it would be loaded on every object that was loaded in the context.

Answer 1

In addition to another answers:

there would be no performance penalty because extension methods is compiler feature. Consider following code:

public static class MyExtensions {     public static void MyMethod(this object) { ... } }   object obj = new object(); obj.MyMethod(); 

The call to MyMethod will be actually compiled to:

MyExtensions.MyMethod(obj); 

Answer 2

There will be no performance penalty as it doesn't attach to every type in the system, it's just available to be called on any type in the system. All that will happen is that the method will show on every single object in intellisense.

The question is: do you really need it to be on object, or can it be more specific. If it needs to be on object, the make it for object.