Button monBouton = new Button(); ComboBox maBox = new ComboBox(); monBouton.Click += new System.EventHandler(monBouton_Click); maBox.SelectedInexChanged += System.EventHandler(maBox_SelectedInexChanged); private void monBouton_Click(object sender, EventArgs e) { if(maBox.Visible == true) maBox.Visible = false; else maBox.Visible = true; } private void maBox_SelectedIndexChanged(object sender, EventArgs e) { monBouton.Text = maBox.SelectedText; maBox.Visible = false; }