Untiy2019版本预制体：

将Unity2019版本做的预制体复制到低版本工程中，发现是不能拖到编辑面板的，如下图：

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编写脚本重新生成预制体：

public class PrefabsToLow : MonoBehaviour
{
    void Start()
    {
        GameObject prefab = Instantiate(UnityEditor.AssetDatabase.LoadAssetAtPath("Assets/Prefabs/Prop particle01.prefab", typeof(GameObject)) as GameObject);
          UnityEditor.PrefabUtility.CreatePrefab("Assets/Prefabs/CubeClone.prefab", prefab);
    }
}

然后就可以拖到编辑面板了，如下图：

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拓展更新，批量生成：

public class PrefabsToLow : MonoBehaviour
{
    void Start()
    {
         for (int n = 0; n < 10; n++)
         {
            GameObject prefab =  Instantiate(UnityEditor.AssetDatabase.LoadAssetAtPath("Assets/Prefabs/Cube"+ n +".prefab", typeof(GameObject)) as GameObject);
            UnityEditor.PrefabUtility.CreatePrefab("Assets/Prefabs/CubeClone.prefab", prefab);
            MonoBehaviour.DestroyImmediate(prefab);
        }
    }
}