ASP.NET Hashtable 对象

创建 Hashtable

Hashtable 对象包含用键/值对表示的项目。键被用作索引，通过搜索其键，可以实现对值的快速搜索。

通过 Add() 方法向 Hashtable 添加项目。

下面的代码创建一个名为 mycountries 的 Hashtable，并添加了四个元素：

Code
<script runat="server">
Sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New Hashtable
  mycountries.Add("C","China")
  mycountries.Add("S","Sweden")
  mycountries.Add("F","France")
  mycountries.Add("I","Italy")
end if
end sub
</script>

数据绑定

Hashtable 对象可为下面这些控件自动地生成文本和值：

asp:RadioButtonList
asp:CheckBoxList
asp:DropDownList
asp:Listbox

如需把数据绑定到某个 RadioButtonList 控件，首先请在一个 .aspx 页面中创建 RadioButtonList 控件（没有任何 asp:ListItem 元素）

Code
<html>
<body>

<form runat="server">
<asp:RadioButtonList id="rb" runat="server" AutoPostBack="True" />

</form>

</body>
</html>

然后添加构建列表的脚本:

Code
<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New Hashtable
  mycountries.Add("C","China")
  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，该例程会在用户点击 RadioButtonList 控件中的某个项目时被执行。当某个单选按钮被点击，label 中会出现一条文本

Code
<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New Hashtable
  mycountries.Add("C","China")
  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>