Hashtable 对象包含用键/值对表示的项目。
尝试一下 - 实例
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>
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>
数据绑定
Hashtable 对象可为下列的控件自动生成文本和值:
- asp:RadioButtonList
- asp:CheckBoxList
- asp:DropDownList
- asp:Listbox
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>
<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>
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:
实例
<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。