Inspector显示Script字段

通过ObjectField就可以轻松实现，问题在于如何获得脚本对象？

MonoScript.FromMonoBehaviour可以获得一个MonoScript对象，而MonoScript继承TextAsset继承Object

GUI.enabled = false;
EditorGUILayout.ObjectField("Script", 
                            MonoScript.FromMonoBehaviour((UIAnimationController)target), 		 															typeof(UIAnimationController), 
                            false);
GUI.enabled = true;

或者直接

serializedObject ??= new SerializedObject (this);
serializedObject.DrawScriptField ();