Variable selection in Dropdown

Hi,

I am new to Design studio and trying to replicate similar functionality in design studio from WAD.

I have a scenario which i am not able to implement. I have a Bex Query, in which in Rows i have Actual current year, Actual previous year and Budget current year, restricted with a variable ZFYEAR (0FISCYEAR) which fetches current year value. In columns i have Jan, Feb march which is restricted with periods. Now in WAD drowdown, we just need to restrict the dropdown with data binding of variable selection and it will work.

In Design studio, i tried on variable initialization APPLICATION.setVariableValue("ZFYEAR", "2015");

and then in startup DROPDOWN_1.setItems(DS_1.getMemberList("0FISCYEAR", MemberPresentation.INTERNAL_KEY, MemberDisplay.KEY, 20));

and then in dropdown event DS_1.setVariableValue("ZFYEAR", DROPDOWN_1.getSelectedValue());

but it is giving me error when i am running.

I need that when i select dropdown values, it should gives that perticular value and default as 2015.

Regards

Nishant