asp.net中不能在DropDownList中选择多个项 原因分析及解决方法

示例代码: 代码如下: BulkStockBll bll = new BulkStockBll(); DataSet ds = bll.GetBulkStock(); this.ddl_BulkStock.DataTextField = “Name” ; this.ddl_BulkStock.DataValueField = “ID” ; this.ddl_BulkStock.DataSource = ds; this.ddl_BulkStock.DataBind(); this.ddl_BulkStock.Items.Add(new ListItem( “全部”, “0” ));//第一次