如果像下面这样写：

using UnityEngine;

using System.Collections;

using UnityEditor;

using System.Collections.Generic;

using UnityEngine.Assertions.Must;

[CustomEditor(typeof(xxxControl))]

public class xxxControlEditor : Editor

{

    SerializedProperty m_a;

    void OnEnable(){

  　　m_a=serializedObject.FindProperty ("m_a");

    }

    public override void OnInspectorGUI()

    {

 　　  /DrawDefaultInspector();

        serializedObject.Update ();

        EditorGUILayout.PropertyField(m_a,true);

        serializedObject.ApplyModifiedProperties ();

    }

}

则在其它Editor或EditorWindow脚本的中调用

    Editor _editor=Editor.CreateEditor(xxxObj.GetComponent<xxxControl>());

就会报如下错误：

NullReferenceException: (null)

UnityEditor.SerializedObject..ctor (UnityEngine.Object[] objs) (at C:/buildslave/unity/build/artifacts/generated/common/editor/SerializedPropertyBindings.gen.cs:72)

UnityEditor.Editor.GetSerializedObjectInternal () (at C:/buildslave/unity/build/artifacts/generated/common/editor/EditorBindings.gen.cs:151)

UnityEditor.Editor.get_serializedObject () (at C:/buildslave/unity/build/artifacts/generated/common/editor/EditorBindings.gen.cs:144)

xxxControlEditor.OnEnable () (at Assets/??/Editor/xxxControlEditor.cs:??)

如果将SerializedObject.FindProperty从OnEnable中改到OnInspectorGUI中，即：

using UnityEngine;

using System.Collections;

using UnityEditor;

using System.Collections.Generic;

using UnityEngine.Assertions.Must;

[CustomEditor(typeof(xxxControl))]

public class xxxControlEditor : Editor

{

    SerializedProperty m_a;

    void OnEnable(){

    }

    public override void OnInspectorGUI()

    {

 　　  /DrawDefaultInspector();

　　  m_a=serializedObject.FindProperty ("m_a");//serializedObject.FindProperty should be called in OnInspectorGUI() instead of OnEnable()

        serializedObject.Update ();

        EditorGUILayout.PropertyField(m_a,true);

        serializedObject.ApplyModifiedProperties ();

    }

}

则不会出现上述错误。