Cloning objects without Serialization

Question

I've found numerous solutions here at SO and elsewere that deal with deep clone of object via serialization/deserialization (into memory and back).

It requires that classes to be cloned are marked with [Serializable]. I happen to have my classes (well most of them) marked with [DataContract] because I use DataContractSerializer to serialize into XML.

I only introduced [Serializable] attribute because of the need for deep clone of some of these class instances. However, now something happened to serialization/deserialization via the DCS because it does not work anymore - errors about expecting a different XML element on deserialization. If I remove the [Serializable] the errors are gone.

What are my options? I just want to deep clone my objects as simple as possible.

Answer 1

This works

    public static T DeepClone<T>(this T a)
    {
        using (MemoryStream stream = new MemoryStream())
        {
            DataContractSerializer dcs = new DataContractSerializer(typeof(T));
            dcs.WriteObject(stream, a);
            stream.Position = 0;
            return (T)dcs.ReadObject(stream);
        }
    }

Answer 2

Json serialization and deserialization should work, it doesn't require the classes to have serialize annotation.

public static T DeepCopy<T>(this T source)
{
    return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(source));
}

Answer 3

Here's how to use it:

var oldList = new List<int>();
var newList = oldList.Clone();

using these Methods:

public static T Clone<T>(this T o) where T : new()
{
    return (T)CloneObject(o);
}
static object CloneObject(object obj)
{
    if (ReferenceEquals(obj, null)) return null;

    var type = obj.GetType();
    if (type.IsValueType || type == typeof(string))
        return obj;
    else if (type.IsArray)
    {
        var array = obj as Array;
        var arrayType = Type.GetType(type.FullName.Replace("[]", string.Empty));
        var arrayInstance = Array.CreateInstance(arrayType, array.Length);

        for (int i = 0; i < array.Length; i++)
            arrayInstance.SetValue(CloneObject(array.GetValue(i)), i);
        return Convert.ChangeType(arrayInstance, type);
    }
    else if (type.IsClass)
    {
        var instance = Activator.CreateInstance(type);
        var fields = type.GetFields(BindingFlags.Public |
                    BindingFlags.NonPublic | BindingFlags.Instance);

        foreach (var field in fields)
        {
            var fieldValue = field.GetValue(obj);
            if (ReferenceEquals(fieldValue, null)) continue;
            field.SetValue(instance, CloneObject(fieldValue));
        }
        return instance;
    }
    else
        return null;
}