private void userToolStripMenuItem_Click(object sender, EventArgs e) { clearChild(); f2 = new FrmUser(); f2.MdiParent = this; f2.Show(); }
private void userToolStripMenuItem_Click(object sender, EventArgs e) { if (f2 == null) { f2 = new FrmUser(); f2.MdiParent = this; f2.Show(); } }