Repeater Component Functionality: Mashup & Drop-Down Values

Hey guys, I need help with creating a Repeater Mashup (for listing workordernum, asset num and drop-down). The drop-down value is populated by calling a service. The Property "Count" is binded to selected drop-down item and the Repeater Mashup is included in List.

Also how do you read the selected drop-down value in the repeater (i.e how to read value from variable "Count") ? If we change the drop-down values in few repeater rows ex : 5 rows out of 100, I need to get only those 5 rows whose drop-down values not empty and modified and pass it to a service.

A step-by-step guide would really help!

Thank you!