ネストクラス（Monobehaviour）のサンプル

SampleCode.cs

using UnityEngine;
using System.Collections;
#if UNITY_EDITOR
using UnityEditor;
#endif

public class SampleCode : MonoBehaviour 
{
	[SerializeField, HideInInspector]
	string label = "none";

	private void Init()
	{
		label = System.DateTime.Now.ToString ();
	}

#if UNITY_EDITOR

	[CustomEditor(typeof(SampleCode))]
	class SampleCodeEditor : Editor
	{
		public override void OnInspectorGUI ()
		{
			EditorGUILayout.LabelField (Instance.label);

			if (GUILayout.Button ("Init")) {
				Instance.Init();
			}
		}

		SampleCode Instance { 
			get{ return (SampleCode)target; }
		}
	}

#endif
}