C#全选和反选

 private void button1_Click(object sender, EventArgs e)
        {
            foreach (Control cn in this.Controls)
            {
                if (cn is CheckBox)
                {
                    CheckBox ch = cn as CheckBox;
                    ch.Checked = true;
                }
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            foreach(Control cc in this.Controls)
            {
                if(cc is CheckBox)
                {
                    CheckBox ch = cc as CheckBox;
                    ch.Checked = false;
                }
            }
        }
    }
}