How Can we verify a Item is present in combo list?

I am new to Robot, I need to verify a particular item or data is present in the Combo List box. I used some commands like SQAFINDOBJECT, SQAWAITFOROBJECT, SQAGETPROPERTY & SQAGETPROPERTYASSTRING. but i couldn't locate that correctly.

finally i have to check particular item is available in the combo list or not. So can anyone find the solution the problem?

For EX:- combo list box contains the following items: RED, GREEN, BLUE. now my problem is to verify whether the item is available or not.

It would be great if you could find the script for this.

Thanks in advance.