String Append in LINQ

Question

hi,
Could any one please suggest a solution for the below scenario in LINQ.

string str = ",employeeName"; // suppose that employee name is a column in employee table.
var q = from e in employee
        select new { e.EmployeeID, str};
in that str place I need to get my column name, in other words I need to select columns based on the value in str.
Thanks in advance !!