Readme.md

What's the point of all this?

The InspectorTypeEnforcerAttribute and the InspectorTypeEnforcerPropertyDrawer classes above will help inform you that a Monobehaviour does not implement a desired interface.

How to install

• InspectorTypeEnforcerAttribute.cs - Put this file in your 'Scripts' folder
• InspectorTypeEnforcerPropertyDrawer.cs - Put this in your 'Editor' folder

How to Use

Throw the [InspectorTypeEnforcer(typeof(YOUR_TYPE_HERE))] attribute on any Serialized property of a MonoBehaviour/ScriptableObject. See the 'TestUsageBehaviour.cs' below for an example.

The Result

Dragging a MonoBehaviour that does not implement the desired interface will turn red when dragged on to the property donned with the attribute.

InspectorTypeEnforcerAttribute.cs

using UnityEngine;
using System;
 
namespace CatchCo
{
   public class InspectorTypeEnforcerAttribute : PropertyAttribute
   {
      public Type EnforcedType;
 
      public InspectorTypeEnforcerAttribute(Type enforcedType)
      {
         EnforcedType = enforcedType;
      }
   }
}

InspectorTypeEnforcerPropertyDrawer.cs

using UnityEngine;
using UnityEditor;
using System;
using CatchCo;
 
namespace CatchCo
{
   [CustomPropertyDrawer(typeof(InspectorTypeEnforcerAttribute))]
   public class InspectorTypeEnforcerPropertyDrawer : PropertyDrawer
   {
      public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
      {
         // save the color temporarily
         var tempColor = GUI.color;
 
         var enforcedType = ((InspectorTypeEnforcerAttribute)attribute).EnforcedType;
         if (property.objectReferenceValue != null && !enforcedType.IsInstanceOfType(property.objectReferenceValue))
         {
            GUI.color = Color.red;
            label.text = "!! " + label.text;
            if (string.IsNullOrEmpty(label.tooltip))
            {
               label.tooltip = "Error: Object does not implement/inherit from Type: " + enforcedType.Name;
            }
         }
         else if (!string.IsNullOrEmpty(label.tooltip))
         {
            label.tooltip = string.Empty;
         }
 
 
         EditorGUI.PropertyField(position, property, label);
 
         // reset color
         GUI.color = tempColor;
      }
   }
}

TestUsageBehaviour.cs

using UnityEngine;
using System.Collections.Generic;
 
namespace CatchCo
{
   public class TestUsageBehaviour : MonoBehaviour
   {
      [InspectorTypeEnforcer(typeof(ITestInterface))]
      public MonoBehaviour TestProperty;
   }
 
   public interface ITestInterface
   {
   }
}