Combox赋值

public Form1()
        {
            InitializeComponent();

            Dictionary<int, string> dic = new Dictionary<int, string>();
            dic.Add(1, "a");
            dic.Add(2, "b");

            foreach (var keyValue in dic)
            {
                this.comboBox1.Items.Add(keyValue);
            }

            DataTable dt = new DataTable();
            dt.Columns.Add("ID", typeof(int));
            dt.Columns.Add("Name", typeof(string));

            dt.Rows.Add(new object[] { 0, "abc0" });
            dt.Rows.Add(new object[] { 1, "abc1" });
            dt.Rows.Add(new object[] { 2, "abc2" });
            dt.Rows.Add(new object[] { 3, "abc3" });
            dt.Rows.Add(new object[] { 4, "abc4" });
            dt.Rows.Add(new object[] { 5, "abc5" });

            
            comboBox2.DisplayMember = "Name";
            comboBox2.ValueMember = "Id";

            //comboBox2.SelectedIndex = 0;
            comboBox2.DataSource = dt;
           
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.textBox1.Text = comboBox1.SelectedItem.ToString();
        }

        private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.textBox2.Text = comboBox2.SelectedValue.ToString() + " : " + comboBox2.Text.ToString();
        }