/全选        private void button3_Click(object sender, EventArgs e)        {            for (int i = 0; i < this.checkedListBox1.Items.Count; i++)            {                this.checkedListBox1.SetItemChecked(i, true);            }}        //反选        private void button4_Click(object sender, EventArgs e)        {            for (int i = 0; i < checkedListBox1.Items.Count; i++)            {                if (checkedListBox1.GetItemChecked(i))                {                    checkedListBox1.SetItemChecked(i, false);                }                else                {                    checkedListBox1.SetItemChecked(i, true);                }            }        }