Hello Pogy,
If I understand correctly, you would like in оnе and the same item, to display the information from all properties of your object. Until now I thought you want to present your data in a grid like format, as you constantly mention RadMultiColumnComboBox, which internally contains a grid.
To achieve the scenario with the custom item, holding information about your object, you will need to use
RadDropDownList with custom visual item. The following article describes how such can be created:
http://www.telerik.com/help/winforms/dropdown-and-listcontrol-listcontrol-visual-data-representation.html.
Alternatively, if you just want to concatenate the property settings and display them below, you can use the
DescriptionTextListDataItem. Here is a small example of this:
Let me know how this works for you.
Regards,
Stefan
Telerik