Iterate through any Property, nested objects and Lists C#

Question

I get 2 objects of Type "Shipment" ("Shipment1" and "Shipment2") and must read each value of them. If the value of Shipment1 is NULL/empty I want to look into the same Value of Shipment2 and if the Value is not NULL/empty I have to copy it to Shipment1. I tried to iterate through my objects with Reflection but the nested Objects "Consignor", "Consignee", "Invoices" let me fail. I hope you can help me. I have the following simplified class structure:

public class Shipment
{
    public int Id { get; set; }
    public Address Consignor { get; set; }
    public Address Consignee { get; set; }
    public IEnumerable<Invoice> Invoices{ get; set; }
} 
public class Address
{
    public string Name { get; set; }
    public string Street{ get; set; }
    public string Zip { get; set; }
    public string City{ get; set; }
    public string Country{ get; set; }
}
public class Invoice
{
    public IEnumerable<Item> Items{ get; set; }
}
public class Item
{
    public string Description{ get; set; }
    public int Amount { get; set; }
}

I tried it this way. It worked for the top level properties of shipment, but not for Consignor, Consignee, Invoices etc.

            foreach (PropertyInfo info1 in shipment1.GetType().GetProperties())
        {
            var datatype = info1.PropertyType;
            switch (datatype.Name.ToLower())
            {
                case "string":

                    if (!string.IsNullOrEmpty((string)info1.GetValue(shipment1)))
                    {
                        string value= (string)info1.GetValue(shipment1);
                        string name = info1.Name;
                        Type type = input.GetType();
                        PropertyInfo info2 = shipment2.GetType().GetProperty(name);


                        if (string.IsNullOrEmpty((string)info2.GetValue(shipment2)))
                        {
                            info2.SetValue(shipment2, value, null);
                        }
                    }
                    break;

                case "integer":
                    // and so on
             }       
       }

Answer 1

I ended up with this, having shipment1 with the same values that shipment2, even if shipment1 was null at the beginning.

Please note that it copies IEnumerable like pointers. After the copy, editing copy.Invoices will also edit source.Invoices, and vice versa.

// used for my test:
Shipment shipment1 = null;
Shipment shipment2 = new Shipment { Id = 42, Consignor = new Address { Name = "Foo1", Street = "Bar1", Zip = "Baz1", City = "Qux1", Country = "Quux1" }, Consignee = new Address { Name = "Foo2", Street = "Bar2", Zip = "Baz2", City = "Qux2", Country = "Quux2" }, Invoices = new Invoice[] { new Invoice { Items = new Item[] { new Item { Description = "FooBar1", Amount = 1 }, new Item { Description = "BazQux1", Amount = 1 } } }, new Invoice { Items = new Item[] { new Item { Description = "FooBar2", Amount = 2 }, new Item { Description = "BazQux2", Amount = 2 } } } } };
// kind of ugly but I didn't manage to do it prettier:
shipment1 = Work(shipment2, shipment1);

private T Work<T>(T source, T copy)
{
    if (source == null)
        return copy;
    if (copy == null)
        copy = Activator.CreateInstance<T>();

    foreach (PropertyInfo prop in typeof(T).GetProperties())
    {
        switch (prop.PropertyType.Name.ToLower())
        {
            case "string":
                string str = (string)prop.GetValue(source);
                if (!string.IsNullOrEmpty(str))
                    if (string.IsNullOrEmpty((string)prop.GetValue(copy)))
                        prop.SetValue(copy, str);
                break;
            case "int32":
                int i = (int)prop.GetValue(source);
                if (i != 0)
                    if ((int)prop.GetValue(copy) == 0)
                        prop.SetValue(copy, i);
                break;
            case "address":
                prop.SetValue(copy, Work(prop.GetValue(source) as Address, prop.GetValue(copy) as Address));
                break;
            case "ienumerable`1":
                switch (prop.PropertyType.GetGenericArguments()[0].Name.ToLower())
                {
                    case "invoice":
                        IEnumerable<Invoice> invoices = (IEnumerable<Invoice>)prop.GetValue(source);
                        if (invoices != null && invoices.Count() > 0)
                            if ((IEnumerable<Invoice>)prop.GetValue(copy) == null)
                                prop.SetValue(copy, invoices);
                        break;
                    // edit: this is actually useless
                    /*
                    case "item":
                        IEnumerable<Item> items = (IEnumerable<Item>)prop.GetValue(source);
                        if (items != null && items.Count() > 0)
                            if ((IEnumerable<Item>)prop.GetValue(copy) == null)
                                prop.SetValue(copy, items);
                        break;
                    */
                }
                break;
        }
    }

    return copy;
}