Question

I want to convert from

 public class Party
 {
        public string Type { get; set; }
        public string Name { get; set; }
        public string Status { get; set;}
 }

and convert to

 public class Contact
 {
        public string Type { get; set; }
        public string Name { get; set; }
        public string Status { get; set;}
        public string Company {get;set;}
        public string Source {get;set;}    
 }

I tried using this extension method

   public static class EnumerableExtensions
    {
        public static IEnumerable<TTo> ConvertTo<TTo, TFrom>(this IEnumerable<TFrom> fromList)
        {
            return ConvertTo<TTo, TFrom>(fromList, TypeDescriptor.GetConverter(typeof(TFrom)));
        }

        public static IEnumerable<TTo> ConvertTo<TTo, TFrom>(this IEnumerable<TFrom> fromList, TypeConverter converter)
        {
            return fromList.Select(t => (TTo)converter.ConvertTo(t, typeof(TTo)));
        }
}

I get this error TypeConverter is unable to convert ‘Party’ to ‘Contact’

    var parties = new List<Party>();
        parties.Add(new Party { Name = "name 1", Status = "status 1" });
        parties.Add(new Party { Name = "name 2", Status = "status 2" });

        var results = parties.ConvertTo<Contact, Party>().ToList();

What am I missing here?

Answer 1

There is no direct conversion between the type Party and the Type contact (polymorphic or inheritance based).

You need to implement a TypeConverter for your types so that .NET knows how to convert between those two types:

MSDN – TypeConverter Class

MSDN – How to Implement a TypeConverter

Once you create your TypeConverters, you have to decorate your two classes with the TypeConverterAttribute so that the Framework can get an instance of your TypeConverter at Runtime:

public class PartyTypeConverter : TypeConverter
{
    // Implementation
}

[TypeConverter(typeof(PartyTypeConverter)]
public class Party
{
    public string Type { get; set; }
    public string Name { get; set; }
    public string Status { get; set; }
}

You could also attempt to mimic the (what I’m guessing) is the desired behavior using LINQ (even though you’ll lose the generic abilities):

var contacts = parties.Select(p => new Contact {
    Type = p.Type,
    Name = p.Name,
    Status = p.Status
});