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HtmlImage.RenderAttributes(HtmlTextWriter) Metode

Definisi

Ruang nama:
System.Web.UI.HtmlControls
Rakitan:
System.Web.dll

Merender HtmlImage atribut kontrol ke objek yang ditentukan HtmlTextWriter .

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)

Parameter

writer
HtmlTextWriter

HtmlTextWriter yang berisi aliran output untuk dirender pada klien.

Pengecualian

HttpException

Properti Src berisi URL yang salah format.

Contoh

Contoh kode berikut menunjukkan cara mengambil alih RenderAttributes metode dalam kontrol server kustom sehingga teks alternatif tertentu, yang dapat diakses sebagai TipsAlat, selalu ditampilkan dengan HtmlImage kontrol.

<%@ 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">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlImage - RenderAttributes - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlImage - RenderAttributes - C# Example</h3>

      <aspSample:CustomHtmlImageRenderAttributes id="Img1"
        runat="server"
        border="0"
        src="image.jpg" />
    </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">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlImage - RenderAttributes - Visual Basic Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlImage - RenderAttributes - Visual Basic Example</h3>

      <aspSample:CustomHtmlImageRenderAttributes id="Img1"
        runat="server"
        border="0"
        src="image.jpg" />
    </form>
  </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlImageRenderAttributes : System.Web.UI.HtmlControls.HtmlImage
    {
        protected override void RenderAttributes(System.Web.UI.HtmlTextWriter writer)
        {
            // Call the base class's RenderAttributes method.
            base.RenderAttributes(writer);
            
            // Write out the HtmlImage control's alt tag.
            writer.Write(" alt=\"Text from custom RenderAttributes method.\"");
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomHtmlImageRenderAttributes
        Inherits System.Web.UI.HtmlControls.HtmlImage

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

            ' Call the base class's RenderAttributes method.
            MyBase.RenderAttributes(writer)

            ' Write out the HtmlImage control's alt tag.
            writer.Write(" alt=""Text from custom RenderAttributes method.""")
        End Sub
    End Class

End Namespace

Keterangan

Jika nilai Src properti adalah URL yang salah bentuk, RenderAttributes metode akan melemparkan HttpException pengecualian.

Metode ini RenderAttributes mengambil alih metode kelas RenderAttributes dasar untuk menulis src atribut kontrol yang dirender HtmlImage .

Metode RenderAttributes ini digunakan terutama oleh pengembang kontrol yang memperluas fungsionalitas HtmlImage kontrol.

Berlaku untuk

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