public void uC_Menu11_UC_Click(object sender, EventArgs e) { zd = new Forms.Zhongdian(); zd.TopLevel = false; zd.Dock = DockStyle.Fill; panel_main.Controls.RemoveAt(0); panel_main.Controls.Add(zd); um.BackgroundImage = Properties.Resources.a; um.FontColor = Color.FromArgb(204, 204, 204); uC_Menu11.BackgroundImage = Properties.Resources.a1; uC_Menu11.FontColor = Color.White; um = uC_Menu11; zd.Tag = sender; zd.Show(); }