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HtmlInputImage.RenderAttributes(HtmlTextWriter) Metode

Definisi

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

Merender HtmlInputImage 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, dapat diakses sebagai TipsAlat, selalu ditampilkan dengan HtmlInputImage.

<%@ 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

Keterangan

Metode RenderAttributes ini menyelesaikan URL yang diatur dalam Src properti, menulis onclick atribut kontrol yang dirender HtmlInputImage jika CausesValidation properti adalah true, dan akhirnya memanggil metode dasar RenderAttributes . Jika nilai Src properti adalah URL cacat, HttpException pengecualian akan dilemparkan.

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

Berlaku untuk

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