ASP.NET Web Forms SortedList 对象

ASP.NET Web Forms SortedList 对象结合了 ArrayList 对象和 Hashtable 对象的特性

范例

  1. SortedList RadiobuttonList 1

  2. SortedList RadiobuttonList 2

  3. SortedList DropDownList

SortedList 对象

SortedList 对象包含用键/值对表示的项目

SortedList 对象按照字母顺序或者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

通过 TrimToSize() 方法把 SortedList 调整为最终尺寸

下面的代码创建了一个名为 mycountries 的 SortedList 对象,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("N","Norway")
    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)

<!DOCTYPE html>
<meta charset="utf-8" />
<form runat="server">
    <asp:RadioButtonList id="rb" runat="server" AutoPostBack="True" />
</form>

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 SortedList
    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>
<!DOCTYPE html>
<meta charset="utf-8" />
<form runat="server">
    <asp:RadioButtonList id="rb" runat="server" AutoPostBack="True" />
</form>

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 SortedList
  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>
<meta charset="utf-8" />
<form runat="server">
<asp:RadioButtonList id="rb" runat="server" AutoPostBack="True" onSelectedIndexChanged="displayMessage" />
<p><asp:label id="lbl1" runat="server" /></p>
</form>

运行范例 »

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