Hi @AnthonyDo
I dont believe you can achieve that directly through ComboBox.
You will need to have a custom column which stores your concatenated values.
Eg: In my case, I had a collection called as coll_Owner. I am using columns Owner and Num from the collection.

Now if I want to use a ComboBox to show me "Owner Num" in a single row in combobox, I'll need to create another collection which stores the concatenated values
ClearCollect(collFinallist,AddColumns(coll_Owner,"Owner + Value",Concatenate(Owner, " ", Num)))
ComboBox
Use collFinallist as my datasource for my combobox.

Either you can add column to your collection OR you can add extra column to your datasource which will hold the concatenated values.
Bit of a pain but I dont believe there is an easy way out of this 🙂
Hope it helps.
-Irfan