private void btnRegister_Click(object sender, EventArgs e)
        {
            if (txtUsername.Text == "")
            {
                MessageBox.Show(SportRegistrationSystem.lblInvalidUsername);
            }
            else
            {
                if (txtPassword.Text == "" || lblPassword.Text.Length < 8)
                {
                    MessageBox.Show(SportRegistrationSystem.lblInvalidPassword);
                }
                else
                {
                    if (txtFullName.Text == "")
                    {
                        MessageBox.Show(SportRegistrationSystem.lblInvalidFullName);
                    }
                    else
                    {
                        bool registrationStatus = StaffBll.RegisterStaff(txtUsername.Text, txtPassword.Text, txtFullName.Text, (int)System.Enum.Parse(typeof (PermissionEnum), cbPermission.SelectedValue.ToString()));
                        MessageBox.Show(registrationStatus
                            ? SportRegistrationSystem.lblRegisterSuccess
                            : SportRegistrationSystem.lblRegisterFailed);
                        if (registrationStatus)
                        {
                            LoginForm form = new LoginForm();
                            form.Show();
                            this.Close();

                        }
                    }
                }
            }
        }
 private void btnCancel_Click(object sender, EventArgs e)
 {
     LoginForm form = new LoginForm();
     form.Show();
     this.Close();
 }