comboBox加载数据

private void button2_Click(object sender, EventArgs e)
        {
            comboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox1.Items.Add("云南");
            comboBox1.Items.Add("上海");
            Class1 c1 = new Class1();
            c1.Id = "01";
            c1.Name = "云南01";
            Class1 c2 = new Class1();
            c2.Id = "02";
            c2.Name = "上海02";
            List<Class1> clist= new List<Class1>();
            clist.Add(c1);
            clist.Add(c2);
            comboBox1.DataSource = clist;
            comboBox1.DisplayMember = "Name";
            comboBox1.ValueMember = "Id";




        }

        private void button3_Click(object sender, EventArgs e)
        {
            if (comboBox1.SelectedValue== null)
            {
                MessageBox.Show("combox里面没有值");
            }
            else
            {
                MessageBox.Show(comboBox1.Text + "/" + comboBox1.SelectedValue.ToString());

            }
           
        }