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Button.AddAttributesToRender(HtmlTextWriter) Metodo

  • Riferimento

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Aggiunge gli attributi del controllo Button al flusso di output per il rendering sul client.

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

Parametri

writer
HtmlTextWriter

Oggetto HtmlTextWriter contenente il flusso di output per il rendering sul client.

Esempio

Nell'esempio di codice seguente viene illustrato come eseguire l'override del AddAttributesToRender metodo in un controllo server personalizzato, in modo che il Button testo venga sempre visualizzato in rosso.

<%@ Page language="c#" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<!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 Button - AddAttributesToRender - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom Button - AddAttributesToRender - C# Example</h3>

      <aspSample:CustomButtonAddAttributesToRender
        id="Button1"
        runat="server"
        Text="Button" />

    </form>
  </body>
</html>

<%@ Page language="VB" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<!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 Button - AddAttributesToRender - VB.NET Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom Button - AddAttributesToRender - VB.NET Example</h3>
      <aspSample:CustomButtonAddAttributesToRender id="Button1" runat="server" Text="Button" />
    </form>
  </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomButtonAddAttributesToRender : System.Web.UI.WebControls.Button
    {
    protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer) 
    {
      // Add a client-side onclick event to the button.
      writer.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Onclick, "alert('Hello World');");

      // Update the text of the button to be shown in the color Red
      writer.AddStyleAttribute(System.Web.UI.HtmlTextWriterStyle.Color, "Red");

      // Call the base's AddAttributesToRender method
      base.AddAttributesToRender(writer);
    }
  }
}

Imports System.Web
Imports System.Security.Permissions

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

        Protected Overrides Sub AddAttributesToRender(ByVal writer As System.Web.UI.HtmlTextWriter)
            ' Add a client-side onclick event to the button.
            writer.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Onclick, "alert('Hello World');")

            ' Update the text of the button to be shown in the color Red
            writer.AddStyleAttribute(System.Web.UI.HtmlTextWriterStyle.Color, "Red")

            ' Call the base's AddAttributesToRender method
            MyBase.AddAttributesToRender(writer)
        End Sub
    End Class
End Namespace ' Samples.AspNet

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