HtmlSelect.Value 属性
定义
获取 HtmlSelect 控件中选定项的值或将该控件的 SelectedIndex 属性设置为具有指定值的列表中的第一个项的索引。Gets the value of the selected item in the HtmlSelect control or sets the SelectedIndex property of the control to the index of the first item in the list with the specified value.
public:
property System::String ^ Value { System::String ^ get(); void set(System::String ^ value); };
public string Value { get; set; }
member this.Value : string with get, set
Public Property Value As String
属性值
HtmlSelect 控件中选定项的值。The value of the selected item in the HtmlSelect control. 如果控件中未选定任何项,则返回 Empty。If no item is selected in the control, Empty is returned.
例外
Value 属性被设置为大于 HtmlSelect 控件中的项数或小于 -1 的项。The Value property was set to an item greater than the number of items in the HtmlSelect control or less than -1.
示例
下面的代码示例演示如何使用 Value 属性获取控件中选定项的值 HtmlSelect 。The following code example demonstrates how to use the Value property to get the value of the selected item in the HtmlSelect control.
<%@ 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> HtmlSelect Example </title>
<script runat="server">
void Button_Click (Object sender, EventArgs e)
{
Label1.Text = "You selected the item with index number " +
Select1.SelectedIndex.ToString() +
" and contains the value " +
Select1.Value + ".";
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3> HtmlSelect Example </h3>
Select items from the list: <br /><br />
<select id="Select1"
runat="server">
<option value="Text for Item 1" selected="selected"> Item 1 </option>
<option value="Text for Item 2"> Item 2 </option>
<option value="Text for Item 3"> Item 3 </option>
<option value="Text for Item 4"> Item 4 </option>
<option value="Text for Item 5"> Item 5 </option>
<option value="Text for Item 6"> Item 6 </option>
</select>
<br /><br />
<button id="Button1"
onserverclick="Button_Click"
runat="server">
Submit
</button>
<br /><br />
<asp:Label id="Label1"
runat="server"/>
</form>
</body>
</html>
<%@ Page Language="VB" 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> HtmlSelect Example </title>
<script runat="server">
Sub Button_Click (sender As Object, e As EventArgs)
Label1.Text = "You selected the item with index number " & _
Select1.SelectedIndex.ToString() & _
" and contains the value " & _
Select1.Value & "."
End Sub
</script>
</head>
<body>
<form id="form1" runat="server">
<h3> HtmlSelect Example </h3>
Select items from the list: <br /><br />
<select id="Select1"
runat="server">
<option value="Text for Item 1" selected="selected"> Item 1 </option>
<option value="Text for Item 2"> Item 2 </option>
<option value="Text for Item 3"> Item 3 </option>
<option value="Text for Item 4"> Item 4 </option>
<option value="Text for Item 5"> Item 5 </option>
<option value="Text for Item 6"> Item 6 </option>
</select>
<br /><br />
<button id="Button1"
onserverclick="Button_Click"
runat="server">
Submit
</button>
<br /><br />
<asp:Label id="Label1"
runat="server"/>
</form>
</body>
</html>
注解
Value属性通常用于获取属性所引用的项的值 SelectedIndex 。The Value property is commonly used to get the value of the item referenced by the SelectedIndex property.
备注
如果控件中未选定任何项,则返回 String.Empty。If no item is selected in the control, String.Empty is returned.
如果将此属性设置为值,则 SelectedIndex 会使用列表中包含该值的第一项的索引来更新属性。If you set this property to a value, the SelectedIndex property is updated with the index of the first item in the list that contains that value. 如果未找到匹配值,则 SelectedIndex 属性保持不变。If no matching value is found, the SelectedIndex property is left unchanged.