Fill Combobox with dynamic values

hi Experts

I want to add combo box values when a form is load. If I do it by Combobox.Validvalues.add function by using loop. it takes lot of times. I also search the same in earlier discussion but they said that you bind the field with the table field where valid values are. but in my case valid values are in different table and I have to save it in different table. For example I want to add Project code (System form Projects-Setup) in combox box in my user defined form comboBox. What should I do.

Thanks

Regards

Jitender Garhwal