Error: Conversion failed when converting the varchar value Fort to data type int for Cascading DropDownList in ASP.Net

I tried your code of cascadingdropdownlist of cuntry,state,city.I want to pass varchar value i.e. text value as parameter to papulate another dropdownlist. I am using following query.

SELECT build_id,build_pin FROM Building WHERE build_area = {0}",country

I am getting following error

Conversion failed when converting the varchar value 'Fort' to data type int.

please tell me how to pass varchar value and please also tell me hw to pass two parameters for where command.