Exporting Data from dataGrid to Excel sheet

Question

Dear All,
I have a Dept Table with DeptId,Name columns
i am binding this table to grid.
on click of a button i am exporting it to excel.

I have other table Emp with EmpId,Name,DeptId
Is their any possiblity on to show the EmployeeName and EmpId on the Click of Dept Id in the excel either in the same sheet or different sheet using C#.
Please help me to solve this issue