ComboBox的数据绑定（新入门，大神勿喷）

//带有ComboBox控件点Load事件
2         private void Library_Load(object sender, EventArgs e)
3         {
4             //创建连接字符串
5             string strConn = "Data Source=.;Initial Catalog=Library;User Id=sa;Pwd=ok";
6             //创建Connection对象
7             SqlConnection conn = new SqlConnection(strConn);
8             //创建DataSet对象
9             DataSet ds = new DataSet();
10             //编写查询语句
11             string sql = "SELECT * FROM BookType";
12             //创建数据适配器对象
13             SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
14             //填充数据到数据集对象中
15             adapter.Fill(ds,"BookType");
16             //在此表中新建一行，显示的值为“请选择”,实际的值为-1
17             DataRow row = ds.Tables["BookType"].NewRow();
18             row[0] = -1;
19             row[1] = "请选择...";
20             ds.Tables["BookType"].Rows.InsertAt(row, 0);
21             //将数据绑定在ComboBox控件中
22             this.cboType.DataSource=ds.Tables["BookType"];
23             this.cboType.ValueMember = "TypeId";
24             this.cboType.DisplayMember = "TypeName";
25         }