using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; namespace 省市联动 { public partial class
1. Class 实体是引用类型,但传入方法时是null的情况在子方法中不论怎么赋值当 FirstService.SetPerson(person,ref tempMsg); 执行后Person都是null:如图1和图2: 但当在 Index2 方法中为person 实例化后就可以如-Person person = new Person ();,当调用FirstService.SetPerson(person,ref tempMsg);方法后person的值会随SetPerson方法中赋值而改变
var dropDownList= document.getElementById("<%=DropDownListID.ClientID %>");//获取DropDownList控件 var dropDownListValue = dropDownList.options[dropDownList.selectedIndex].value;//获取选择项的值 //注:DropDownListID是DropDownList控件的ID. JS验证是否有非0值: -- if