Hi,
Sounds OK - but if you don't really need a datatable then if's very simple to use a generic list instead. A couple of generic methods will convert any list of objects to XML and back (assuming the objects themselves are serializable). e.g:

public static class Helper
    {
        public static List<T> RetrieveList<T>(string s)
        {
            XmlSerializer xs = new XmlSerializer(typeof(List<T>));
            System.Xml.XmlReader v = System.Xml.XmlReader.Create(new StringReader(s));
            return (List<T>)xs.Deserialize(v);
        }

        public static string ConvertToXML<T>(List<T> list)
        {
            XmlSerializer xs = new XmlSerializer(typeof(List<T>));
            StringWriter sw = new StringWriter();
            xs.Serialize(sw, list);
            return sw.ToString();
        }
    }

Example use:

       List<Contact> list = new List<Contact>();
            list.Add(new Contact { Name = "Fred", Age = 33 });
            list.Add(new Contact { Name = "Joe", Age = 66 });

            string xmlString = Helper.ConvertToXML<Contact>(list);
            //(Examine this string to determine what VFP should create)

            List<Contact> retrievedList = Helper.RetrieveList<Contact>(xmlString);

>Thanks for the tip. In the meantime, I've decided to switch to sending XML and convert that to a DataTable that I can iterate through. That seems to do the trick for now.
>
>Jon
>
>>>My C# COM DLL has a public method with the following signature:
>>>

>>>public void AddClientsToList(Contact[] contacts, string listName)
>>>

>>>
>>>In VFP, I do the following:

• Call a DLL method to get a new contact object
• Populate the properties
• Create an array and place the object in the first element
• Call COMARRAY(loDLL,10)

>>>When I attempt loDLL.AddClientsToList(@MyArray, "test"), I get a type mismatch COM error.
>>>
>>>Any ideas on what I'm doing wrong?
>>
>>No. But passing arrays of anything is always a pain. Since you have control of both sides maybe it would be simpler to just pass the Contacts in one-by-one? e.g:

public class MyDll
>>    {
>>        Dictionary<string, List<Contact>> lists = new Dictionary<string, List<Contact>>();
>>        public Contact GetNewContact() { return new Contact();}
>>       
>>        public void AddClientToList(Contact contact,string listName)
>>        {
>>             if (!lists.Keys.Contains(listName))
>>                lists.Add(listName, new List<Contact>());
>>            lists[listName].Add(contact);
>>        }
>>    }