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ASP.NET Web Forms - 教程

ASP.NET - SortedList 对象

SortedList 对象兼有 ArrayList 和 Hashtable 对象的特性。

实例

SortedList RadiobuttonList 1
SortedList RadiobuttonList 2
SortedList DropDownList

SortedList 对象

SortedList 对象包含用键/值对表示的项目。SortedList 对象可按照字符顺序或数字顺序自动地对项目进行排序。

通过 Add() 方法向 SortedList 添加项目。SortedList 可通过 TrimToSize() 方法调整为最终尺寸。

下面的代码创建了一个名为 mycountries 的 SortedList,并添加了四个元素:

<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New SortedList
  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

SortedList 对象可自动地为下面的控件生成文本和值:

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

如需把数据绑定到 RadioButtonList 控件,首先请在 aspx 文件中创建一个 RadioButtonList 控件(没有任何 asp:ListItem 元素):

<html>
<body>

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

</body>
</html>

然后添加构建列表的脚本:

<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New SortedList
  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,该子例程会在用户点击 RadioButtonList 控件中的项目时执行。当单选按钮被点击时,文本将出现在 label 中:

<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  dim mycountries=New SortedList
  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>

显示这个例子

WebForms Hashtable

WebForms XML文件

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