共用方式為

HtmlInputImage.Alt 屬性

  • 參考

定義

命名空間:
System.Web.UI.HtmlControls
組件:
System.Web.dll

取得或設定在沒有影像或尚未下載完成時，瀏覽器將顯示的替代文字。

public:
 property System::String ^ Alt { System::String ^ get(); void set(System::String ^ value); };
public string Alt { get; set; }
member this.Alt : string with get, set
Public Property Alt As String

屬性值

String

指定影像的替代文字。 預設值為空字串 ("")。

範例

下列程式碼範例示範如何使用 Alt 屬性來指定要在影像無法使用時顯示的替代文字。

<%@ 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>

備註

Alt使用 屬性可指定要在指定的影像無法使用或尚未下載時顯示的文字。 您也可以使用這個屬性，以程式設計方式判斷指定的替代文字。

在支援工具提示功能的瀏覽器中，此文字也會顯示為控制項的工具 HtmlInputImage 提示。

適用於

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