private void testToolStripMenuItem_Click(object sender, EventArgs e) { util u1 = new util(); Node <PO> pn = de.work_pl.Head; while (pn != null) { if (!u1.Test_l_l(pn.Data.ll, pn.Data)) { pn.Data.key = 5; } pn = pn.Next; } ogl1.PlotGLKey(); }