Hashtable 对象包含用键/值对表示的项目。
Hashtable 对象包含用键/值对表示的项目。键被用作索引,通过搜索键,可以实现对值的快速搜索。
通过 Add() 方法向 Hashtable 添加项目。
下面的代码创建了一个名为 mycountries 的 Hashtable 对象,并添加了四个元素:
< script runat = "server" > Sub Page_Load if Not Page.IsPostBack then dim mycountries=New Hashtable mycountries.Add("N","Norway") mycountries.Add("S","Sweden") mycountries.Add("F","France") mycountries.Add("I","Italy") end if end sub </ script > |
Hashtable 对象可为下列的控件自动生成文本和值:
为了绑定数据到 RadioButtonList 控件,首先要在 .aspx 页面中创建一个 RadioButtonList 控件(不带任何 asp:ListItem 元素):
< html > < body > < form runat = "server" > < asp:RadioButtonList id = "rb" runat = "server" AutoPostBack = "True" /> </ form > </ body > </ html > |
然后添加创建列表的脚本,并且绑定列表中的值到 RadioButtonList 控件:
< script runat = "server" > sub Page_Load if Not Page.IsPostBack then dim mycountries=New Hashtable mycountries.Add("N","Norway") mycountries.Add("S","Sweden") mycountries.Add("F","France") mycountries.Add("I","Italy") rb.DataSource=mycountries rb.DataValueField="Key" rb.DataTextField="Value" rb.DataBind() end if end sub </ script > < html > < body > < form runat = "server" > < asp:RadioButtonList id = "rb" runat = "server" AutoPostBack = "True" /> </ form > </ body > </ html > |
然后我们添加一个子例程,当用户点击 RadioButtonList 控件中的某个项目时,该子例程会被执行。当某个单选按钮被点击时,label 中会出现一行文本:
< script runat = "server" > sub Page_Load if Not Page.IsPostBack then dim mycountries=New Hashtable mycountries.Add("N","Norway") mycountries.Add("S","Sweden") mycountries.Add("F","France") mycountries.Add("I","Italy") rb.DataSource=mycountries rb.DataValueField="Key" rb.DataTextField="Value" rb.DataBind() end if end sub sub displayMessage(s as Object,e As EventArgs) lbl1.text="Your favorite country is: " & rb.SelectedItem.Text end sub </ script > < html > < body > < form runat = "server" > < asp:RadioButtonList id = "rb" runat = "server" AutoPostBack = "True" onSelectedIndexChanged = "displayMessage" /> < p >< asp:label id = "lbl1" runat = "server" /></ p > </ form > </ body > </ html > |
注释:您无法选择添加到 Hashtable 的项目的排序方式。如需对项目进行字母排序或者数字排序,请使用 SortedList 对象。