private void AddProduct_Click(object sender, EventArgs e)
{
currentItem = new InvoiceItem();
currentItem.ProductID = 0;
ShowProducts form = new ShowProducts(currentItem);
form.FormClosed += ShowProductFormClosed;
form.ShowDialog();
}
private void ShowProduccts_Click(object sender, EventArgs e)
{
ShowProducts form = new ShowProducts();
form.ShowDialog();
}