private void diagnosticoToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (ForDiagnostico == null)
            {
                DataTable Tabla = new DataTable();
                Tabla = UsuarioNegocio.LoginVerificar(DNI);

                ForDiagnostico             = new FrmDiagnostico();
                ForDiagnostico.MdiParent   = this;
                ForDiagnostico.EmpleadoDni = Convert.ToString(Tabla.Rows[0][0]);
                ForDiagnostico.FormClosed += new FormClosedEventHandler(CerrarForma2);
                ForDiagnostico.Show();
            }
            else
            {
                ForDiagnostico.Activate();
            }
        }
 void CerrarForma2(object sender, FormClosedEventArgs e)
 {
     ForDiagnostico = null;
 }