HtmlButton.OnPreRender(EventArgs) Método

Referência

Definição

Namespace:: System.Web.UI.HtmlControls

Assembly:: System.Web.dll

Importante

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Gera o evento PreRender e registra o script de cliente para gerar um postback.

protected:
 override void OnPreRender(EventArgs ^ e);

protected public:
 override void OnPreRender(EventArgs ^ e);

protected override void OnPreRender (EventArgs e);

protected internal override void OnPreRender (EventArgs e);

override this.OnPreRender : EventArgs -> unit

Protected Overrides Sub OnPreRender (e As EventArgs)

Protected Friend Overrides Sub OnPreRender (e As EventArgs)

Parâmetros

e: EventArgs

Um EventArgs que contém dados do evento.

Exemplos

O exemplo de código a seguir demonstra como substituir o OnPreRender método em um controle de servidor personalizado para que ele sempre exiba o HtmlButton com texto em negrito.

<%@ 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 HtmlButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        HtmlButton1.Attributes.Add("onclick","alert('Hello client-side world.');");
      }

      void HtmlButton1_ServerClick(Object sender, EventArgs e)
      {
        Div1.InnerHtml = "Hello server-side world.";
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Html Button</aspSample:CustomHtmlButtonOnPreRender>  

      <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">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        HtmlButton1.Attributes.Add("onclick", "alert('Hello client-side world.');")
      End Sub

      Sub HtmlButton1_ServerClick(sender As Object, e As EventArgs)
        Div1.InnerHtml = "Hello server-side world."
      End Sub
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Button</aspSample:CustomHtmlButtonOnPreRender>  

      <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 CustomHtmlButtonOnPreRender : System.Web.UI.HtmlControls.HtmlButton
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);

            // Always display the HtmlButton with bold text.
            this.Style.Add("font-weight", "bold");
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

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

        Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)

            ' Call the base class's OnPreRender method.
            MyBase.OnPreRender(e)

            ' Always display the HtmlButton with bold text.
            Me.Style.Add("font-weight", "bold")
        End Sub
    End Class

End Namespace

Comentários

O OnPreRender método é usado principalmente por desenvolvedores de controle que estendem a funcionalidade do HtmlButton controle.

Aplica-se a

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