Persistently changing variables from custom editor

Hi everyone,

I have a script that has a custom class as a field, such as this:

public class MyClass : Monobehaviour{
     public GameObject prefab; // a prefab that has a MyClass component
     public SomeClass someClass;
}

public class SomeClass{
     public int x;

     public SomeClass(int _x){
          x = _x;
     }
}

What I’m trying to do is instantiate gameobjects with a MyClass component attached to them via a custom inspector for MyClass. Specifically, I want to set the someClass field to a specific value. Im currently trying it as follows:

[CustomEditor (typeof(MyClass))]
public class MyClassEditor : Editor{
     public override void OnInspectorGUI() {
        DrawDefaultInspector();
        
        MyClass mc = (MyClass) target;

        if(GUILayout.Button("button")) {
            GameObject go = (GameObject) Instantiate(mc.prefabToInstantiate);
            go.GetComponent<MyClass>().someClass.x = 1;
        }
     }
}

This does indeed instantiate the desired object and sets x to 1. However, as soon as I start the game, the field x is not set to 1 anymore. Is there any way to make this value persistent, even when entering play mode?

Cheers.

You will need to make the SomeClass serializable for it to retain the data.

So what happens here is, when unity enters playmode, all the data that is stored in C# side (like the values in the inspector) is serialized and restored back after the assemblies are reloaded.

UPDATE: In case if you’re wondering why did I specify “C# side”, Unity’s core engine code is split into 2 parts, managed (C#) and native (C++). In order to change the state of the editor (like Enter / Exit playmode for example), Unity undergoes an internal assembly reload.

So any data that needs to survive this assembly reload should be serializable by the editor.

I got it to work by making SomeClass inherit from ScriptableObject. I’m not sure exactly why this solves the problem, but it does. Maybe this will help someone in the future.