Thanks for the reply.
I am getting the data for two dropdowns from two different services which results in an infotable with one column(key_name) each, I am binding the all data of each service to its corresponding dropdown data , assigning the display field to key_name. Now i'm binding values of "popupMash" mashup parameters key1 and key2 to selected text of two dropdowns , assigning the value field to key_name. after this changes also, i am unable to see the selected text in dropdowns.
I need some info: is there any property "selected value" for dropdown . I am using thingworx7.1.3 version. I can see only display field, value field and selected text properties.