Cannot serialize member… because it is an interface

Question

I have been having this problem and been pulling my hair out over it. I have the followin error:

Exception Details: System.NotSupportedException: Can

Answer 1

Not the source of your problem, but you need

using (MemoryStream memoryStream = new MemoryStream())
{
    serializer.Serialize(memoryStream, this);
    memoryStream.Seek(0, SeekOrigin.Begin);
    using (StreamReader reader = new StreamReader(memoryStream))
    {
        return reader.ReadToEnd();
    }
}

Answer 2

In the code you posted, the type of CustomerAddresses is IList<CustomerAdress>. That's an interface. Like the error message says, you can't serialize an interface.