private void btnLogin_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrWhiteSpace(txtUserName.Text) || string.IsNullOrWhiteSpace(txtPassword.Text))
                return;

            try
            {
                IUserService userService = new UserService();
                bool isUserAuthorized = false; // userService.ValidateUser(txtUserName.Text, txtPassword.Text);
                if (!isUserAuthorized)
                {
                    lblError.Text = "Invalid user name or password. Please try again.";
                    return;
                }
                MainForm mainForm = new MainForm();
                mainForm.Show();
                //this.Close();
                this.Hide();
            }
            catch (Exception)
            {
                throw;
            }
        }
 private void button1_Click(object sender, EventArgs e)
 {
     MainForm main = new MainForm();
     main.Show();
 }