sap ui 5 adding Odata service to combobox.

i want to add Odata service to combobox , i am developing (Desktop app,commons,used .js file) 

Scenario-

see                                  ( for each item value is set.. when i clicked on item 1 it should return value in another textfield)

                         combobx 1     

                             item 1                                                 supposed  number 5 is assigned to item 1

                             item 2

                             item 3                                                       it should be return on textfield.

                                                                                            i have already created Odata service.

Help 'll be appreciate..