GUI Extension methods

Unity Engine
1

So I want to make an extension to the Unity gui via C# extension functions.

I am going

static public bool SlideToggle(this GUI gui)
{
return true;
}

However when I then do:
GUI.SlideToggle()
which it autocompletes that.

It gives the error:
Assets/Scripts/ProductView/ProductViewGUIControl.cs(97,21): error CS0117: UnityEngine.GUI' does not contain a definition for SlideToggle’

How do I make an extension class for UnityEngine.GUI???

2

You can’t extend GUI, GUILayout, EditorGUI, or EditorGUILayout in this way.

From the MSDN page on Extension Methods:

This means that you can’t add static methods to classes. The GUI classes only use static methods. You will see the autocomplete/intellisense correctly if you create an instance of GUI, but it would be the only method you could access.

GUI.SlideToggle() // will not work.

GUI myGUI = new GUI();
myGUI.SlideToggle(); // Will work, but it's weird to use GUI this way.

You should create your own GUI container class. This will allow you to separate controls and keep things organized.

C#

public static class MyGUI
{
   public static bool SlideToggle(bool value)
   {
      // Handle Slide Toggle control here.
   }
}
3

Right. As Eddy said, you should keep your (static) GUI methods within your namespace.

Extension methods are a syntactic sugar that should be avoided, because you have no guarantee that other component author won’t decide to use the same name when extending some class, so you have clashes!