private void bar_DSBDVHX_LinkClicked(object sender, DevExpress.XtraNavBar.NavBarLinkEventArgs e)
 {
     if (formDLBDVHX == null || formDLBDVHX.IsDisposed)
     {
         formDLBDVHX           = new QL_DaiLyBuuDienVHX();
         formDLBDVHX.MdiParent = this;
         formDLBDVHX.Show();
     }
     else
     {
         formDLBDVHX.Activate();
     }
 }
 private void button_dlbdvhx_Click(object sender, EventArgs e)
 {
     if (formDLBDVHX == null || formDLBDVHX.IsDisposed)
     {
         formDLBDVHX           = new QL_DaiLyBuuDienVHX();
         formDLBDVHX.MdiParent = this;
         formDLBDVHX.Show();
     }
     else
     {
         formDLBDVHX.Activate();
     }
 }