private void btn_login_Click(object sender, EventArgs e)
        {
            string name     = txt_name.Text;
            string password = txt_password.Text;

            if (!(name == string.Empty) && !(password == string.Empty))
            {
                bool result = _login.ValidateUser(name, password);
                if (result)
                {
                    MessageBox.Show("Login Sucessful", "",
                                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                    this.Hide();
                    MainForm main = new MainForm(name);
                    main.ShowDialog();
                    Close();
                }
                else
                {
                    MessageBox.Show("Fail!", "Error",
                                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }
            else
            {
                MessageBox.Show("Plz enter password and username", "Error",
                                MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        private void btn_login_Click(object sender, EventArgs e)
        {
            string name = txt_name.Text;
            string pwd  = txt_password.Text;

            if (_login.ValidateUser(name, pwd))
            {
                MessageBox.Show("Welcome Login Sucessful", "Information",
                                MessageBoxButtons.OK, MessageBoxIcon.Information);
                _currentuser = name;
                MainForm.SetName(name, _main);
                Hide();
            }
        }