private void penjualan_btn_Click(object sender, EventArgs e)
{
if (penjualanPage == null)
{
penjualanPage = new adpenjualan(); //Create form if not created
penjualanPage.FormClosed += penjualanPage_FormClosed; //Add eventhandler to cleanup after form closes
InitializeComponent();
penjualanPage.Show(this); //Show Form assigning this form as the forms owner
}
}
void penjualanPage_FormClosed(object sender, FormClosedEventArgs e)
{
penjualanPage = null;
Show();
}