private void Window_Loaded(object sender, RoutedEventArgs e)
{
lblDisplay.Content = "Display all member!..";
StaffClient staff = new StaffClient();
string s = staff.DisplayStaff();
lblDisplay.Content = " " + s;
}
static void Main(string[] args)
{
StaffClient client = new StaffClient();
string s = client.DisplayStaff();
Console.WriteLine(s);
client.Close();
}