Parameterizing values in dropdown in Truclient

Hello All,

I was trying to parameterize the values from drop down in Truclient.

Its the address which I have to type it then it will fetch the related addresses where I have to select any address.

I tried parameterizing this , It didnt work. Can anyone let me know how will we parameterize the values in Truclient. 

I was using TC.getParam("Address") instead of the actual address, however it didnt worked. 

Pls suggest.

Screenshot attached for reference.