ASP.NET - SortedList 對(duì)象
SortedList 對(duì)象兼有 ArrayList 和 Hashtable 對(duì)象的特性。
SortedList 對(duì)象
SortedList 對(duì)象包含用鍵/值對(duì)表示的項(xiàng)目。SortedList 對(duì)象可按照字符順序或數(shù)字順序自動(dòng)地對(duì)項(xiàng)目進(jìn)行排序。
通過(guò) Add() 方法向 SortedList 添加項(xiàng)目。SortedList 可通過(guò) TrimToSize() 方法調(diào)整為最終尺寸。
下面的代碼創(chuàng)建了一個(gè)名為 mycountries 的 SortedList，并添加了四個(gè)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>
數(shù)據(jù)綁定
SortedList 對(duì)象可自動(dòng)地為下面的控件生成文本和值：
- asp:RadioButtonList
- asp:CheckBoxList
- asp:DropDownList
- asp:Listbox
如需把數(shù)據(jù)綁定到 RadioButtonList 控件，首先請(qǐng)?jiān)?aspx 文件中創(chuàng)建一個(gè) RadioButtonList 控件（沒(méi)有任何 asp:ListItem 元素）：
<html>
<body>
<form runat="server">
<asp:RadioButtonList id="rb" runat="server" AutoPostBack="True" />
</form>
</body>
</html>
然后添加構(gòu)建列表的腳本：
<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>
然后我們添加一個(gè)子例程，該子例程會(huì)在用戶點(diǎn)擊 RadioButtonList 控件中的項(xiàng)目時(shí)執(zhí)行。當(dāng)單選按鈕被點(diǎn)擊時(shí)，文本將出現(xiàn)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>