.net - merging two objects in C#

Question

I have an object model MyObject with various properties. At one point, I have two instances of these MyObject: instance A and instance B. I'd like to copy and replace the properties in instance A with those of instance B if instance B has non-null values.

If I only had 1 class with 3 properties, no problem, I could easily hard code it (which is what I started doing). But I actually have 12 different object models with about 10 properties each.

What's good way to do this?

Answer 1

Update Use AutoMapper instead if you need to invoke this method a lot. Automapper builds dynamic methods using Reflection.Emit and will be much faster than reflection.'

You could copy the values of the properties using reflection:

public void CopyValues<T>(T target, T source)
{
    Type t = typeof(T);

    var properties = t.GetProperties().Where(prop => prop.CanRead && prop.CanWrite);

    foreach (var prop in properties)
    {
        var value = prop.GetValue(source, null);
        if (value != null)
             prop.SetValue(target, value, null);
    }
}

I've made it generic to ensure type safety. If you want to include private properties you should use an override of Type.GetProperties(), specifying binding flags.