//Constructor
public MainForm()
{
InitializeComponent();
_presentationModel = new PresentationModel(this);
_loginForm = new LoginForm(_presentationModel);
_presentationModel.AddFormToPanel(_loginForm);
}
private void comfirmButton(object sender, EventArgs e)
{
PostProduct();
LoginForm lgf = new LoginForm();
this.Hide();
lgf.Show();
}