Reflection Cloning Class variables

I'm trying to write a function that will copy the values from one class variable to another.
Here is what I have so far. What am I doing wrong?

Code (CSharp):

1.     public object Copy(object value)
2.     {
3.         object instance = AbilityAOE.CreateInstance(value.GetType());
4.         foreach (FieldInfo info in value.GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.FlattenHierarchy))
5.         {
6.             if (info.FieldType.IsClass)
7.                 info.SetValue(instance, Copy(info.GetValue(value)));
8.             else
9.                 info.SetValue(instance, info.GetValue(value));
10.         }
11.         return instance;
12.     }

 

Nothing... except maybe "AbilityAOE.CreateInstance"

Did you mean Activator.CreateInstance?

 

Ok I tried this.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using System.Reflection;
4.  
5.  
6. public class Test : MonoBehaviour {
7.  
8.     public AbilityAOE fromAOE;
9.     public AbilityAOE toAOE;
10.  
11.     public AbilityAOE abilityAoe;
12.  
13.     void Start ()
14.     {
15.         abilityAoe = (AbilityAOE)Copy(fromAOE);
16.     }
17.  
18.  
19.     public object Copy(object value)
20.     {
21.         object instance = System.Activator.CreateInstance(value.GetType());
22.         foreach (FieldInfo info in value.GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.FlattenHierarchy))
23.         {
24.             if (info.FieldType.IsClass)
25.                 info.SetValue(instance, Copy(info.GetValue(value)));
26.             else
27.                 info.SetValue(instance, info.GetValue(value));
28.         }
29.         return instance;
30.     }
31.  
32. }
33.  

The AbilityAOE's are ScriptableObjects. May that be the problem?
It gives me this error:

Code (CSharp):

1. NullReferenceException: Object reference not set to an instance of an object
2. Test.Copy (System.Object value) (at Assets/AbilitySystem/Test.cs:21)
3. Test.Copy (System.Object value) (at Assets/AbilitySystem/Test.cs:25)
4. Test.Start () (at Assets/AbilitySystem/Test.cs:15)
5.  

 

Well, if you have one field being null, you need to pass that over without trying to "copy" it. "null.GetType()" doesn't work too well.

 

I'm getting this error now:

Code (CSharp):

1. MissingMethodException: Method not found: 'Default constructor not found...ctor() of System.String'.
2. System.Activator.CreateInstance (System.Type type, Boolean nonPublic) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System/Activator.cs:368)
3. System.Activator.CreateInstance (System.Type type) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System/Activator.cs:254)
4. Test.Copy (System.Object value) (at Assets/AbilitySystem/Test.cs:21)
5. Test.Copy (System.Object value) (at Assets/AbilitySystem/Test.cs:28)
6. Test.Start () (at Assets/AbilitySystem/Test.cs:15)
7.  

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using System.Reflection;
4.  
5.  
6. public class Test : MonoBehaviour {
7.  
8.     public AbilityAOE fromAOE;
9.     public AbilityAOE toAOE;
10.  
11.     public AbilityAOE abilityAoe;
12.  
13.     void Start ()
14.     {
15.         abilityAoe = (AbilityAOE)Copy(fromAOE);
16.     }
17.  
18.  
19.     public object Copy(object value)
20.     {
21.         object instance = System.Activator.CreateInstance(value.GetType());
22.         foreach (FieldInfo info in value.GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.FlattenHierarchy))
23.         {
24.             if (info.GetValue(value) == null)
25.                 continue;
26.  
27.             if (info.FieldType.IsClass)
28.                 info.SetValue(instance, Copy(info.GetValue(value)));
29.             else
30.                 info.SetValue(instance, info.GetValue(value));
31.         }
32.         return instance;
33.     }
34.  
35. }
36.  

 

Yeah... Welcome to the amazing world of copying by reflection.

Code (csharp):

1. if (data is string)
2.     return ((string)data).Clone();

You will have issues if there is no empty constructor, but nothing you can do about it.

You will also need to test for ScriptableObject since those need to be created with ScriptableObject.CreateInstance instead of the Activator.

 

So if your AbilityAOE is ScriptableObject you can just use Instantiate to make a full copy of that.(with Unity serialization rules)

 

I got it working with strings and Textures however I am getting errors when it tries copying generic Lists and Enums. Any ideas?

Code (CSharp):

1.     public object Copy(object value)
2.     {
3.         object copy = ScriptableObject.CreateInstance(value.GetType());
4.         foreach (FieldInfo propertyInfo in value.GetType().GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.FlattenHierarchy))
5.         {
6.             if (propertyInfo.GetValue(value) == null)
7.                 continue;
8.  
9.             Debug.Log (propertyInfo.Name);
10.  
11.             if (propertyInfo.FieldType.IsClass)
12.             {
13.                 if (propertyInfo.GetValue(value) is string)
14.                     propertyInfo.SetValue(copy, (string)propertyInfo.GetValue(value));
15.                 else
16.                     if (propertyInfo.GetValue(value) is Texture)
17.                         propertyInfo.SetValue(copy, (Texture)propertyInfo.GetValue(value));
18.                 else
19.                 {
20.  
21.                     propertyInfo.SetValue(copy, Copy(propertyInfo.GetValue(value)));
22.              
23.                 }
24.             }else
25.                 propertyInfo.SetValue(copy, propertyInfo.GetValue(value));
26.         }
27.         return copy;
28.     }

Error:

Code (CSharp):

1. TargetException: Non-static field requires a target
2. System.Reflection.MonoField.SetValue (System.Object obj, System.Object val, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Reflection/MonoField.cs:123)
3. System.Reflection.FieldInfo.SetValue (System.Object obj, System.Object value) (at

 

Oh geez... You really want a full bullet-proof copy? Mine in my AdvancedInspector is like 400 lines, handling array, list, dictionary and so on.

In case of collection, you have to create a collection with the same size, and copy each element over to the new collection. Usually, for an array, you would do Array.CreateInstance ( http://msdn.microsoft.com/en-us/library/system.array.createinstance(v=vs.110).aspx ) as for the a list, the default constructor (Activator.CreateInstance) works just fine.

 

This works perfectly! Thanks!

Code (CSharp):

1. object copy = Instantiate((Object)value);