object name is not saved after scene reload

Question

I have a simple script that changes name of an object, but changed name is not remembered when I change scenes.

public class MyBehaviour : MonoBehaviour
{
#if UNITY_EDITOR
    private void OnValidate()
    {
        if (!this.name.Contains("_")) 
        {
            this.name = $"{this.name}_{this.GenUID()}";
        }
    }
#endif
}

How can I save changes made via script in Edit-Mode?

Answer 1

You will have to mark you object dirty so it will be saved when hitting CTRL+S

EditorUtility.SetDirty

You can use SetDirty when you want to modify an object without creating an undo entry, but still ensure the change is registered and not lost. If the object is part of a Scene, the Scene is marked dirty.

public class MyBehaviour : MonoBehaviour
{
#if UNITY_EDITOR
    private void OnValidate()
    {
        if (!this.name.Contains("_")) 
        {
            this.name = $"{this.name}_{this.GenUID()}";
            EditorUtility.SetDirty(this);
        }
    }
#endif
}

Also note

If the object may be part of a Prefab instance, you additionally need to call PrefabUtility.RecordPrefabInstancePropertyModifications to ensure a Prefab override is created.

And if you want to also support Undo/Redo

If you do want to support undo, you should not call SetDirty but rather use Undo.RecordObject prior to making changes to an object, since this will both mark the object as dirty (or the object's Scene if it is part of a Scene) and provide an undo entry in the editor. You should still also call PrefabUtility.RecordPrefabInstancePropertyModifications if the object may be part of a Prefab instance.