HtmlInputRadioButton.OnPreRender(EventArgs) Método

Referência

Definição

Namespace:: System.Web.UI.HtmlControls

Assembly:: System.Web.dll

Importante

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Aciona o evento PreRender e registra o controle HtmlInputRadioButton como um que requer manipulação de 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 os dados do evento.

Exemplos

O exemplo de código a seguir demonstra como substituir o OnPreRender método para que ele adicione um Title atributo em um controle de servidor personalizado HtmlInputRadioButton .

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ 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 HtmlInputRadioButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e) 
      {
        Div1.InnerHtml = "";
      }

      void HtmlInputRadioButtonGroup1_ServerChange(object sender, System.EventArgs e)
      {
        // Diplay the value of the selected HtmlInputRadioButton control.
        System.Web.UI.HtmlControls.HtmlInputRadioButton htmlInputRadioButtonGroup1 = (System.Web.UI.HtmlControls.HtmlInputRadioButton) sender;
        Div1.InnerHtml = "You change your selection to: " + htmlInputRadioButtonGroup1.Value;
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputRadioButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton1" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" checked
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton1">HtmlInputRadioButton1
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>
      <br />

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton2" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" 
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton2">HtmlInputRadioButton2
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>

      <p>
        <input type="submit" value="Submit" id="Submit1" name="Submit1" runat="server" />
      </p>
      
      <div 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
    </form>
  </body>
</html>

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ 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 HtmlInputRadioButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        Div1.InnerHtml = ""
      End Sub

      Sub HtmlInputRadioButtonGroup1_ServerChange(sender As Object, e As System.EventArgs)
        Dim htmlInputRadioButtonGroup1 As System.Web.UI.HtmlControls.HtmlInputRadioButton  = CType(sender, System.Web.UI.HtmlControls.HtmlInputRadioButton)
        Div1.InnerHtml = "You change your selection to: " & htmlInputRadioButtonGroup1.Value
      End Sub
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputRadioButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton1" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" checked
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton1">HtmlInputRadioButton1
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>
      <br />

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton2" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" 
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton2">HtmlInputRadioButton2
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>

      <p>
        <input type="submit" value="Submit" id="Submit1" name="Submit1" runat="server" />
      </p>
      
      <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 CustomHtmlInputRadioButtonOnPreRender : System.Web.UI.HtmlControls.HtmlInputRadioButton
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Run the OnPreRender method on the base class.
            base.OnPreRender(e);
            
            // Add a Title attribute.
            this.Attributes.Add("title", "Option " + this.Value);
        }
    }
}

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

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

        ' Run the OnPreRender method on the base class.
        MyBase.OnPreRender(e)

        ' Add a Title attribute.
        Me.Attributes.Add("title", "Option " + Me.Value)
    End Sub
End Class

Comentários

O OnPreRender método é chamado pouco antes de renderizar o HtmlInputRadioButton controle.

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

Aplica-se a

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