public TList<Employees> GetEmployeesHiredBetween(DateTime startDate, DateTime endDate)
        {
            EmployeesParameterBuilder pb = new EmployeesParameterBuilder();
            pb.AppendRange(EmployeesColumn.HireDate, startDate.ToString(), endDate.ToString());

            return DataRepository.EmployeesProvider.Find(pb.GetParameters());
        }

EmployeesService ES = new EmployeesService();
        TList<Employees> List = ES.GetEmployeesHiredBetween(Convert.ToDateTime(this.TextBox1.Text), Convert.ToDateTime(this.TextBox2.Text));
        this.GridView1.DataSource = List;
        this.GridView1.DataBind();