Call a function from CustomPropertyDrawer of Arbitrary class

Hi, So I have this class

public class SomeClass {
   public int number;
   public void SomeFunction() {}

This class is used in many part of my GameObject components, so If i want to create a custom editor for this class, i have to use CustomPropertyDrawer.

public class ComExpressionEditor : PropertyDrawer

	public override void OnGUI (Rect position, SerializedProperty property, GUIContent label)
                     // Do something magic here.

But how i can call my SomeFunction() from there? I’ve tried property.serializedObject.targetObject but it makes a compiler error since my SomeClass is an arbitrary (Not Unity.Object) class. Is there any workaround for this?

That’s actually not possible with massive useage of reflection as a SerializedProperty only represents the seraializable data and not the actual class instances. Classes derived from UnityEngine.Object are a different story. For those (usually MonoBehaviour or ScriptableObjects) you can use SerializedProperty.objectReferenceValue to get the serialized reference to that object. However if it’s just a serializable custom class the serialization system doesn’t even know that instance exists. It’s content is simply serialized along with the containing MonoBehaviour object (or ScriptableObject).

As i said there are ways to access the “current” instance by using reflection as shown by HiddenMonk and Johannski over here.

Despite it’s possible, it’s not a good approach. Unity’s serialization system abstracted the data from the actual objects. A SerializedObject / SerializedProperty just represents the actual stored data and not the concrete object. Any manipulation is ment to be done through the SerializedProperty class.

I know this system has some limitations when it comes to more complex structures. If you really need to directly access a class instance you would need to use a seperate CustomEditor. PropertyDrawers aren’t designed for what you want to do. They are ment to work on the abstracted representation. Keep in mind that a SerializedProperty can actually represent multiple objects at once in case you have more than one object selected.

A custom editor can access the any members of the MonoBehaviour / ScriptableObject through the “target” / “targets” variable(s). In that case you have to handle everything yourself including registering undo operations.