Ernst,

>how can I populate a mmcombobox with the field names of a business object

To populate a combo box with property names of a business object you need to use .NET reflection to get the names of the properties. Here is an article that discusses how to do this:

http://www.c-sharpcorner.com/UploadFile/harishankar2005/Reflectionin.NET12032005045926AM/Reflectionin.NET.aspx

Best Regards,