c# combox 同时写入和获取 text ，value

public class ComboBoxItem   //新建一个类储存值
        {
            private string _text = null;
            private object _value = null;
            public string Text { get { return this._text; } set { this._text = value; } }
            public object Value { get { return this._value; } set { this._value = value; } }
            public override string ToString()
            {
                return this._text;
            }
        }  
        private void Form1_Load(object sender, EventArgs e)
        {

           // 存入 text 和 value
            int ss = 0;
            for (int i = 0; i < 10; i++)
            {

            ComboBoxItem newItem = new ComboBoxItem();
            newItem.Text = i.ToString();
            ss = i + 100;
            newItem.Value = ss.ToString();
            comboBox1.Items.Add(newItem);
            }
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

         //textbox 中显示combox选中项的value

            textBox1.Text = ((ComboBoxItem)comboBox1.Items[comboBox1.SelectedIndex]).Value.ToString();
        }