ListItem.Value 属性
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
获取或设置与 . ListItem.
public:
property System::String ^ Value { System::String ^ get(); void set(System::String ^ value); };public string Value { get; set; }member this.Value : string with get, setPublic Property Value As String属性值
与 . ListItem. 关联的值 默认值为 Empty。
示例
注释
下面的代码示例使用单文件代码模型，如果直接复制到代码隐藏文件中，可能无法正常工作。 必须将此代码示例复制到扩展名为 .aspx 的空文本文件中。 有关 Web 窗体代码模型的详细信息，请参阅 ASP.NET Web 窗体页代码模型。
<!-- The following example demonstrates adding items to and removing items
from ListBox controls. When an item is selected in ListBox1, a new ListBoxItem with
the same value can be created and added to ListBox2, if ListBox2 does not already
contain an item with that value. When the new ListBoxItem is created, it receives
the Value property of the selected item as its Text property, and the Text property
of the selected item as its value property. -->
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ListItem Example</title>
<script runat="server">
void AddBtn_Click(Object Sender, EventArgs e)
{
if (ListBox1.SelectedIndex > -1)
{
if (ListBox2.Items.FindByValue(ListBox1.SelectedItem.Text) == null)
{
ListItem Item = new ListItem();
// Text and Value are swapped.
Item.Text = ListBox1.SelectedItem.Value;
Item.Value = ListBox1.SelectedItem.Text;
ListBox2.Items.Add(Item);
}
}
}
void DelBtn_Click(Object Sender, EventArgs e)
{
if (ListBox2.SelectedIndex > -1)
{
ListBox2.Items.Remove(ListBox2.SelectedItem);
}
}
</script>
</head>
<body>
<h3>ListItem Example</h3>
<form id="form1" runat="server">
<table>
<tr><td>
<asp:ListBox id="ListBox1" Width="100px" runat="server">
<asp:ListItem Value="Value 1">Item 1</asp:ListItem>
<asp:ListItem Value="Value 2">Item 2</asp:ListItem>
<asp:ListItem Value="Value 3">Item 3</asp:ListItem>
<asp:ListItem Value="Value 4">Item 4</asp:ListItem>
<asp:ListItem Value="Value 5" Selected="True">Item 5</asp:ListItem>
<asp:ListItem Value="Value 6">Item 6</asp:ListItem>
</asp:ListBox>
</td><td>
<asp:button Text="--->" OnClick="AddBtn_Click" runat="server" /><br />
<asp:button Text="<---" OnClick="DelBtn_Click" runat="server" />
</td><td>
<asp:ListBox id="ListBox2" Width="100px" runat="server"/>
</td></tr>
</table>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!-- The following example demonstrates adding items to and removing items
from ListBox controls. When an item is selected in ListBox1, a new ListBoxItem with
the same value can be created and added to ListBox2, if ListBox2 does not already
contain an item with that value. When the new ListBoxItem is created, it receives
the Value property of the selected item as its Text property, and the Text property
of the selected item as its value property. -->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ListItem Example</title>
<script language="VB" runat="server">
Sub AddBtn_Click(Sender As Object, e As EventArgs)
If ListBox1.SelectedIndex > -1 Then
If ListBox2.Items.FindByValue(ListBox1.SelectedItem.Text) is Nothing Then
Dim Item As ListItem = new ListItem()
'Text and Value are swapped
Item.Text = ListBox1.SelectedItem.Value
Item.Value = ListBox1.SelectedItem.Text
ListBox2.Items.Add(Item)
End If
End If
End Sub
Sub DelBtn_Click(Sender As Object, e As EventArgs)
If ListBox2.SelectedIndex > -1 Then
ListBox2.Items.Remove(ListBox2.SelectedItem)
End If
End Sub
</script>
</head>
<body>
<h3>ListItem Example</h3>
<form id="form1" runat="server">
<table>
<tr><td>
<asp:ListBox id="ListBox1" Width="100px" runat="server">
<asp:ListItem Value="Value 1">Item 1</asp:ListItem>
<asp:ListItem Value="Value 2">Item 2</asp:ListItem>
<asp:ListItem Value="Value 3">Item 3</asp:ListItem>
<asp:ListItem Value="Value 4">Item 4</asp:ListItem>
<asp:ListItem Value="Value 5" Selected="True">Item 5</asp:ListItem>
<asp:ListItem Value="Value 6">Item 6</asp:ListItem>
</asp:ListBox>
</td><td>
<asp:button Text="--->" OnClick="AddBtn_Click" runat="server" /><br />
<asp:button Text="<---" OnClick="DelBtn_Click" runat="server" />
</td><td>
<asp:ListBox id="ListBox2" Width="100px" runat="server"/>
</td></tr>
</table>
</form>
</body>
</html>
注解
使用 Value 属性指定或确定与 . ListItem关联的值。
注释
Value如果该属性包含null，则get访问器返回该属性的值Text。 如果返回属性Text，则返回属性包含nullString.Empty。
设置此属性的值可以使用设计器工具自动保存到资源文件中。 有关详细信息，请参阅LocalizableAttribute全球化和本地化。
