DataSource ='<%# GetStudentInfo( Convert.ToInt16(Eval("Department_Id")) )%>'

public DataTable GetStudentsByDepartment(int DepartmentId)

   {

       SqlConnection dbConnection = new SqlConnection(ConnectionString);
       DataTable dtStudentList = new DataTable();
       try

       {
           dbConnection.Open();
           SqlDataAdapter daStudents = new SqlDataAdapter();
           SqlCommand cmdSelect = new SqlCommand("SelectStudentByDep",dbConnection);
           cmdSelect.CommandType = CommandType.StoredProcedure;
           cmdSelect.Parameters.AddWithValue("@Dep", DepartmentId );
           daStudents.SelectCommand = cmdSelect;
           daStudents.Fill(dtStudentList);

       }

       catch (Exception objException)

       {
           HttpContext.Current.Response.Write(objException.Message);
       }

      finally

       {
           if (dbConnection != null && dbConnection.State == ConnectionState.Open)
           {
               dbConnection.Close();
           }
       }
       return dtStudentList;
   }