Xforms to data-provider parameter passing

xquery

I am trying to achieve parameter passing from xforms to data-provider xml to resolve performance issue.
Let us assume ,In my first drop down shows country value. Based on the first drop down (country) selection second drop down (state) value needs to be displayed in run-time.
For example:If i select country "India" in the first drop down,respective state(assam,kerala) value needs to be displayed in the second drop down in run-time.could you please help to me to achieve this using parameter passing from xforms to data provider xml.