private void CheckUser(object sender, RoutedEventArgs e)
        {
            mainDal check = new mainDal();

            if (teacher.IsChecked.Equals(true))
            {
                if (check.Login(this.username.Text, this.password.Password, "teacher"))
                {
                    adminBoard a = new adminBoard();
                    name    = this.username.Text;
                    a.Name1 = name;
                    a.Show();
                }
                else
                {
                    MessageBox.Show("Invalid Password");
                }
            }
            else if (student.IsChecked.Equals(true))
            {
                if (check.Login(this.username.Text, this.password.Password, "student"))
                {
                    studentBoard s = new studentBoard();
                    s.Name1 = this.username.Text;
                    s.Show();
                }
                else
                {
                    MessageBox.Show("Invalid Password");
                }
            }
        }