ComboBox数据的绑定

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