readme

Author: quabug

Assets/Sample/MyMonoBehavior.cs

@@ -0,0 +1,11 @@
+using GenericSerializeReference;
+using UnityEngine;
+
+public interface IMyInterface<T> {}
+public class MyIntObject : IMyInterface<int> {}
+public struct StructWillNotShow : IMyInterface<int> {}
+public class MyMonoBehavior : MonoBehaviour
+{
+    [GenericSerializeReference]
+    public IMyInterface<int> Value { get; set; }
+}

Assets/Sample/MyMonoBehavior.cs.meta

@@ -133,6 +133,7 @@ GameObject:
   m_Component:
   - component: {fileID: 366887100}
   - component: {fileID: 366887099}
+  - component: {fileID: 366887101}
   m_Layer: 0
   m_Name: GameObject
   m_TagString: Untagged
@@ -220,3 +221,21 @@ Transform:
   m_Father: {fileID: 0}
   m_RootOrder: 0
   m_LocalEulerAnglesHint: {x: 0, y: 0, z: 0}
+--- !u!114 &366887101
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 366887098}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: 810f573826344204a49b76ad339a67e3, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: 
+  _Value:
+    id: 0
+  references:
+    version: 1
+    00000000:
+      type: {class: , ns: , asm: }

Assets/Sample/Test.unity

@@ -1,2 +1,58 @@
-# GenericSerializeReference
-Make a field with generic type serializable by mark with [GenericSerializeReference] attribute.
+```c#
+public interface IMyInterface<T> {}
+public class MyIntObject : IMyInterface<int> {}
+
+public class MyMonoBehavior : MonoBehaviour
+{
+    [GenericSerializeReference]
+    public IMyInterface<int> Value { get; set; }
+}
+```
+![image](https://user-images.githubusercontent.com/683655/111064372-b47b6280-84ee-11eb-90c2-22cfbdc65cc0.png)
+
+# Limitations
+- Only types from referenced assemblies could be show up in inspector.
+- Not support `struct` type
+
+# Costs
+- Extra time to generate IL instructions while building assembly
+- Extra memory space to store a generated field for each property.
+
+# How it works
+```c#
+public class MyMonoBehavior : MonoBehaviour
+{
+    // [GenericSerializeReference]
+    // public IMyInterface<int> Value { get; set; }
+
+    // 1. gather derived types of property (`IMyInterface<>`)
+    //    then generate a concrete version of those types and make them all implement `IBase` interface
+    private static class <Value>__generic_serialize_reference
+    {
+        public interface IBase {}
+        public class MyIntObject : global::MyIntObject, IBase {}
+    }
+
+    // 2. create a field named _Value with `IBase` type
+    //    which should be able to serialized by `SerializeReference` attribute
+    [SerializeReference, GenericSerializeReferenceGeneratedField]
+    private <Value>__generic_serialize_reference.IBase _Value;
+    
+    // 3. inject code into property's getter and setter
+    //    make sure property get value from serialized field first
+    //    and set serialized field into null to avoid get from it next time.
+    [GenericSerializeReference]
+    public IMyInterface<int> Value
+    {
+        get
+        {
+            return (IMyInterface<int>) _Value ?? <Value>k__backingField;
+        }
+        set
+        {
+            <Value>k__backingField = value;
+            _Value = null;
+        }
+    }
+}
+```