private void btnHangSX_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
frmHangSX hangsx = new frmHangSX();
hangsx.MdiParent = this;
hangsx.Show();
}
private void btnHangSX_Click(object sender, EventArgs e)
{
frmHangSX Hang = null;
if (Hang == null || Hang.IsDisposed)
{
Hang = new frmHangSX();
}
Hang.ShowDialog();
}