Question

I have a problem cloning dynamic object with the code like this:

    public void Execute(IPrepareData entity)
    {
        try
        {                
            dynamic data = entity.Primary as dynamic;
            data.PreviousInfo = deepClone(data.Info);
        }
        catch (Exception ex)
        {
            data.Errors.Add(ex.Message);
        }
    }

    private static T deepClone<T>(T obj)
    {
        if (typeof(T).IsClass || typeof(T).IsArray)
        {
            if (ReferenceEquals(obj, null))
            {
                return default(T);
            }
        }
        using (var memoryStream = new MemoryStream())
        {
            BinaryFormatter fieldFormatter = new BinaryFormatter();
            fieldFormatter.Serialize(memoryStream, obj);
            memoryStream.Position = 0;
            return (T)fieldFormatter.Deserialize(memoryStream);
        }
    }

    dynamic data;

I don’t know the structure of entity in advance (only that it will contain Info, and I don’t know the structure of info) and that it won’t be marked serializable. I need to copy this info to previous info section of entity.

Result of execution of this code is ‘Object reference not set to an instance of an object’ on fieldFormatter.Serialize line.

How can I check if it is an instance of an object?

There might be (most probably will be) circular references, so I am not trying reflection as I am not sure how to deal with that. Also speed is not an issue.

Answer 1

If you don’t know that the data will be marked serializable, then you can’t rely on using BinaryFormatter.

If the object is likely to have circular references, a lot of other serializers are out of the question.

If we assume it is the general case of dynamic (and not just ExpandoObject), then there is no way of getting information about the members, since they can be invented as they are queried.

Basically, this scenario *has no good answer. There is no magic way to just deep clone “a thing”.