共用方式為

HtmlInputImage.RenderAttributes(HtmlTextWriter) 方法

  • 參考

定義

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

將 HtmlInputImage 控制項的屬性轉譯為指定的 HtmlTextWriter 物件。

protected:
 override void RenderAttributes(System::Web::UI::HtmlTextWriter ^ writer);
protected override void RenderAttributes (System.Web.UI.HtmlTextWriter writer);
override this.RenderAttributes : System.Web.UI.HtmlTextWriter -> unit
Protected Overrides Sub RenderAttributes (writer As HtmlTextWriter)

參數

writer
HtmlTextWriter

HtmlTextWriter，包含在用戶端上呈現的輸出資料流。

例外狀況

HttpException

Src 屬性包含不正確的 URL。

範例

下列程式碼範例示範如何在自訂伺服器控制項中覆寫 RenderAttributes 方法，以便一律以 工具提示的形式存取 HtmlInputImage 特定的替代文字。

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ 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">
<script runat="server">
  
  void Page_Load(Object sender, EventArgs e)
  {
    
    // Set the OnClick attribute of the custom HtmlInputImage control.
    HtmlInputImage1.Attributes.Add("onclick", "alert('Hello client-side world.');");
  }

  void HtmlInputImage1_ServerClick(Object sender, ImageClickEventArgs e)
  {

    // Set the inner HTML of the div element.
    Div1.InnerHtml = "Hello server-side world.";
    
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom HtmlInputImage - RenderAttributes - C# Example</title>
    </head>
    <body>
        <form id="form1" runat="server">
            <h3>Custom HtmlInputImage - RenderAttributes - C# Example</h3>
        
          <aspSample:CustomHtmlInputImageRenderAttributes 
            id="HtmlInputImage1" 
            name="HtmlInputImage1"
            runat="server" 
            type="image" 
                    src="Image1.jpg"
                    alt="Microsoft"
                    onserverclick="HtmlInputImage1_ServerClick" />
     
      <br />
      <br />

      <div 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"/>
        
        </form>
    </body>
</html>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ 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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    ' Set the OnClick attribute of the custom HtmlInputImage control.
    HtmlInputImage1.Attributes.Add("onclick", "alert('Hello client-side world.');")

  End Sub

  Sub HtmlInputImage1_ServerClick(ByVal sender As Object, ByVal e As ImageClickEventArgs)

    ' Set the inner HTML of the div element.
    Div1.InnerHtml = "Hello server-side world."

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom HtmlInputImage - RenderAttributes - Visual Basic Example</title>
    </head>
    <body>
        <form id="form1" runat="server">
            <h3>Custom HtmlInputImage - RenderAttributes - Visual Basic Example</h3>
        
          <aspSample:CustomHtmlInputImageRenderAttributes 
            id="HtmlInputImage1"
            name="HtmlInputImage1"
            runat="server" 
            type="image" 
                    src="Image1.jpg"
                    alt="Microsoft"
                    onserverclick="HtmlInputImage1_ServerClick" />
     
      <br />
      <br />

      <div 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"/>
        
        </form>
    </body>
</html>

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlInputImageRenderAttributes : System.Web.UI.HtmlControls.HtmlInputImage
    {
        protected override void RenderAttributes(System.Web.UI.HtmlTextWriter writer)
        {
            // Add an Alt attribute to the HtmlInputImage control.
            writer.Write(" alt='Alternate text from RenderAttributes'");
            
            // Call the base class's RenderAttributes method.
            base.RenderAttributes(writer);
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomHtmlInputImageRenderAttributes
        Inherits System.Web.UI.HtmlControls.HtmlInputImage

        Protected Overrides Sub RenderAttributes(ByVal writer As System.Web.UI.HtmlTextWriter)

            ' Add an Alt attribute to the HtmlInputImage control.
            writer.Write(" alt='Alternate text from RenderAttributes'")

            ' Call the base class's RenderAttributes method.
            MyBase.RenderAttributes(writer)
        End Sub
    End Class
End Namespace

備註

方法 RenderAttributes 會解析 屬性中設定的 Src URL、如果 CausesValidation 屬性為 true ，則寫入 onclick 轉譯 HtmlInputImage 控制項的 屬性，最後呼叫基底 RenderAttributes 方法。 如果屬性的值 Src 是格式不正確的 URL， HttpException 則會擲回例外狀況。

方法 RenderAttributes 主要是由控制項開發人員用來擴充控制項的功能 HtmlInputImage 。

適用於

另請參閱