Web Forms - Hashtable 对象

Hashtable 对象包含用键/值对表示的项目。

在线实例

Hashtable RadiobuttonList 1

<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>

<!DOCTYPE html>
<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>

Hashtable RadiobuttonList 2

<script  runat="server">
sub Page_Load
if Not Page.IsPostBack then
   dim navigate=New Hashtable
   navigate.Add("RadioButtonList","control_radiobuttonlist.asp")
   navigate.Add("CheckBoxList","control_checkboxlist.asp")
   navigate.Add("DropDownList","control_dropdownlist.asp")
   navigate.Add("ListBox","control_listbox.asp")
   rb.DataSource=navigate
   rb.DataValueField="Value"
   rb.DataTextField="Key"
   rb.DataBind()
end if
end sub

sub navigate(s as Object, e As EventArgs)
response.redirect(rb.SelectedItem.Value)
end sub
</script>

<!DOCTYPE html>
<html>
<body>

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

</body>
</html>

Hashtable DropDownList

<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")
   dd.DataSource=mycountries
   dd.DataValueField="Key"
   dd.DataTextField="Value"
   dd.DataBind()
end if
end sub

sub displayMessage(s as Object,e As EventArgs)
lbl1.text="Your favorite country is: " & dd.SelectedItem.Text
end sub
</script>

<!DOCTYPE html>
<html>
<body>

<form runat="server">
<asp:DropDownList id="dd" runat="server"
AutoPostBack="True" onSelectedIndexChanged="displayMessage" />
<p><asp:label id="lbl1" runat="server" /></p>
</form>

</body>
</html>

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>

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>

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：

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。