private void dangNhapToolStripMenuItem_Click(object sender, EventArgs e)
{
frmLog _frmLog = new frmLog(this);
_frmLog.MdiParent = this;
_frmLog.Show();
}
public frmMain()
{
InitializeComponent();
frmLog _frmLog = new frmLog(this);
_frmLog.Show();
}