HtmlInputButton.OnPreRender(EventArgs) Method

Reference

Definition

Namespace:: System.Web.UI.HtmlControls

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Raises the OnPreRender(EventArgs) event and registers client script for generating 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)

Parameters

e: EventArgs

An EventArgs that contains the event data.

Examples

The following code example demonstrates how to override the OnPreRender method so that it always displays a custom HtmlInputButton control with bold text.

ASP.NET (C#)

<%@ 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 HtmlInputButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        HtmlInputButton1.Attributes.Add("onclick","alert('Hello client-side world.');");
      }

      void HtmlInputButton1_ServerClick(Object sender, EventArgs e)
      {
        Div1.InnerHtml = "Hello server-side world.";
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlInputButtonOnPreRender
        id="HtmlInputButton1"
        runat="server"
        type="button"
        onserverclick="HtmlInputButton1_ServerClick"
        value="Html Input Button"
        name="HtmlInputButton1">  

      <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 HtmlInputButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        HtmlInputButton1.Attributes.Add("onclick", "alert('Hello client-side world.');")
      End Sub

      Sub HtmlInputButton1_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 HtmlInputButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlInputButtonOnPreRender
        id="HtmlInputButton1"
        runat="server"
        type="button"
        onserverclick="HtmlInputButton1_ServerClick"
        value="Html Input Button"
        name="HtmlInputButton1">  

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

            // Always display the HtmlInputButton 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 CustomHtmlInputButtonOnPreRender
        Inherits System.Web.UI.HtmlControls.HtmlInputButton

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

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

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

End Namespace

Remarks

The OnPreRender method overrides the Control.OnPreRender method. OnPreRender is used primarily by control developers.

Applies to

Product	Versions
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

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