C# extension methods on GameObject?

I'm trying to extend GameObject with C# extension methods, for example:

Code (csharp):

1.  
2. using ExtensionMethods;
3.  
4. GameObject foo = new GameObject("foo");
5. foo.SendMessage("test");
6.  
7. // elsewhere
8. namespace ExtensionMethods
9. {
10.     internal static class ExtendGameObject
11.     {
12.         public static void SendMessage(this GameObject go, string methodName)
13.         {
14.             Debug.Log(methodName);
15.         }
16.     }
17. }
18.  

The above code won't work - the regular method is called. If I change the two instances of "SendMessage" to "SendMessageEx" then it works fine - my method is called.

What am I doing wrong?

 

Because send message is an existing function.

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class example : MonoBehaviour {
6.     void ApplyDamage(float damage) {
7.         print(damage);
8.     }
9.     void Example() {
10.         gameObject.SendMessage("ApplyDamage", 5.0F);
11.     }
12. }
13.  

 

Ah, what I'm doing is misunderstanding extension methods!

You can't override, existing methods with same name always hide the extension method.

edit - @Sinister, thanks