private void BtnSellItems_Click(object sender, EventArgs e)
{
if (SaleForm != null)
{
SaleForm.Show();
}
else
{
SaleForm = new FrmGetPersonForSale();
SaleForm.Closed += SaleForm_Closed;
SaleForm.Show();
}
}
void SaleForm_Closed(object sender, EventArgs e)
{
SaleForm = null;
}