Possibility to define parent type for the [ReferencePicker] attribute

Author: arimger

Assets/Editor Toolbox/Editor/Drawers/Toolbox/PropertySelf/ReferencePickerAttributeDrawer.cs

@@ -13,9 +13,8 @@ public class ReferencePickerAttributeDrawer : ToolboxSelfPropertyDrawer<Referenc
         private readonly TypeField typeField = new TypeField(new TypeConstraintReference(null));
 
 
-        private void CreateTypeProperty(SerializedProperty property)
+        private void CreateTypeProperty(SerializedProperty property, Type parentType)
         {
-            property.GetFieldInfo(out Type propertyType);
             TypeUtilities.TryGetTypeFromManagedReferenceFullTypeName(property.managedReferenceFullTypename, out var currentType);
             var position = EditorGUILayout.GetControlRect(false, EditorGUIUtility.singleLineHeight);
             position = EditorGUI.IndentedRect(position);
@@ -44,7 +43,7 @@ private void CreateTypeProperty(SerializedProperty property)
                 {
                     ToolboxEditorLog.LogWarning("Invalid attempt to update disposed property.");
                 }
-            }, currentType, propertyType);
+            }, currentType, parentType);
         }
 
         private void UpdateTypeProperty(SerializedProperty property, Type referenceType)
@@ -55,6 +54,24 @@ private void UpdateTypeProperty(SerializedProperty property, Type referenceType)
             property.serializedObject.ApplyModifiedProperties();
         }
 
+        private Type GetParentType(SerializedProperty property, ReferencePickerAttribute attribute)
+        {
+            property.GetFieldInfo(out Type propertyType);
+            var candidateType = attribute.ParentType;
+            if (candidateType != null)
+            {
+                if (propertyType.IsAssignableFrom(candidateType))
+                {
+                    return candidateType;
+                }
+
+                ToolboxEditorLog.AttributeUsageWarning(attribute, property,
+                    $"Provided {nameof(attribute.ParentType)} ({candidateType}) cannot be used because it's not assignable from: '{propertyType}'");
+            }
+
+            return propertyType;
+        }
+
 
         protected override void OnGuiSafe(SerializedProperty property, GUIContent label, ReferencePickerAttribute attribute)
         {
@@ -66,7 +83,8 @@ protected override void OnGuiSafe(SerializedProperty property, GUIContent label,
                 }
 
                 EditorGUI.indentLevel++;
-                CreateTypeProperty(property);
+                var parentType = GetParentType(property, attribute);
+                CreateTypeProperty(property, parentType);
                 ToolboxEditorGui.DrawPropertyChildren(property);
                 EditorGUI.indentLevel--;
             }

Assets/Editor Toolbox/Runtime/Attributes/Toolbox/PropertySelfAttributes/ReferencePickerAttribute.cs

@@ -12,6 +12,16 @@ namespace UnityEngine
     [AttributeUsage(AttributeTargets.Field, AllowMultiple = false)]
     [Conditional("UNITY_EDITOR")]
     public class ReferencePickerAttribute : ToolboxSelfPropertyAttribute
-    { }
+    {
+        public ReferencePickerAttribute()
+        { }
+
+        public ReferencePickerAttribute(Type parentType)
+        {
+            ParentType = parentType;
+        }
+
+        public Type ParentType { get; set; }
+    }
 }
 #endif

Assets/Examples/Scenes/SampleScene.unity

@@ -581,20 +581,26 @@ MonoBehaviour:
     id: 0
   var2:
     id: 1
+  var3:
+    id: 2
   references:
     version: 1
     00000000:
       type: {class: SampleBehaviour6/ClassWithInterface1, ns: , asm: Assembly-CSharp}
       data:
         go: {fileID: 977748987}
         var1:
-          id: 2
+          id: 3
     00000001:
+      type: {class: SampleBehaviour6/ClassWithInterface3, ns: , asm: Assembly-CSharp}
+      data:
+        var1: 31
+    00000002:
       type: {class: SampleBehaviour6/ClassWithInterface2, ns: , asm: Assembly-CSharp}
       data:
         var1: 0
         mat: {fileID: 2100000, guid: 7404c70251f9d0045a4aabaa49d83963, type: 2}
-    00000002:
+    00000003:
       type: {class: SampleBehaviour6/Struct, ns: , asm: Assembly-CSharp}
       data:
         var1: 1

Assets/Examples/Scripts/SampleBehaviour6.cs

@@ -11,6 +11,8 @@ public class SampleBehaviour6 : MonoBehaviour
     public Interface1 var1;
     [SerializeReference, ReferencePicker]
     public ClassWithInterfaceBase var2;
+    [SerializeReference, ReferencePicker(ParentType = typeof(ClassWithInterface2))]
+    public ClassWithInterfaceBase var3;
 #endif
 
     public interface Interface1 { }
@@ -49,4 +51,10 @@ public class ClassWithInterface3 : ClassWithInterfaceBase
     {
         public int var1;
     }
+
+    [Serializable]
+    public class ClassWithInterface4 : ClassWithInterface2
+    {
+        public int var33;
+    }
 }