HtmlInputImage.Alt 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。
获取或设置当图像不可用或尚未下载时浏览器显示的替换文本。
public:
property System::String ^ Alt { System::String ^ get(); void set(System::String ^ value); };public string Alt { get; set; }member this.Alt : string with get, setPublic Property Alt As String属性值
所指定图像的替换文本。 默认值为空字符串 ("")。
示例
下面的代码示例演示如何使用 Alt 属性指定要在图像不可用时显示的备用文本。
<%@ 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" >
<script runat="server">
protected void SubmitBtn_Click(object sender, ImageClickEventArgs e)
{
Message.InnerHtml = "The Submit button was clicked.";
}
protected void ClearBtn_Click(object sender, ImageClickEventArgs e)
{
Message.InnerHtml = "The Clear button was clicked.";
}
</script>
<head runat="server">
<title>HtmlInputImage Example</title>
</head>
<body>
<h3>HtmlInputImage Example</h3>
<form id="form1" runat="server">
<input type="image"
alt="Submit button"
src="Submit.jpg"
onserverclick="SubmitBtn_Click"
runat="server"
id="Image1" />
<input type="image"
alt="Clear button"
src="Clear.jpg"
onserverclick="ClearBtn_Click"
runat="server"
id="Image2" />
<h1>
<span id="Message"
runat="server">
</span>
</h1>
</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">
<script runat="server">
Sub SubmitBtn_Click(ByVal Source As Object, ByVal E As ImageClickEventArgs)
Message.InnerHtml = "The Submit button was clicked."
End Sub
Sub ClearBtn_Click(ByVal Source As Object, ByVal E As ImageClickEventArgs)
Message.InnerHtml = "The Clear button was clicked."
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HtmlInputImage Example</title>
</head>
<body>
<h3>HtmlInputImage Example</h3>
<form id="form1" runat="server">
<input type="image"
alt="Submit button"
src="Submit.jpg"
onserverclick="SubmitBtn_Click"
runat="server"
id="Image1" />
<input type="image"
alt="Clear button"
src="Clear.jpg"
onserverclick="ClearBtn_Click"
runat="server"
id="Image2" />
<h1>
<span id="Message"
runat="server">
</span>
</h1>
</form>
</body>
</html>
注解
使用此属性 Alt 指定要在指定图像不可用或尚未下载时显示的文本。 还可以使用此属性以编程方式确定指定的可选文本。
在支持工具提示功能的浏览器中，此文本也显示为控件的工具提示 HtmlInputImage 。