HtmlInputCheckBox.OnPreRender(EventArgs) Method
Definition
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 the control as one that requires postback handling.
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
Examples
The following code example demonstrates how to override the OnPreRender method in a custom server control so that a Title
attribute is added to each HtmlInputCheckBox control.
<%@ 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 HtmlInputCheckBox - OnPreRender - C# Example</title>
<script runat="server">
void Button1_Click(Object sender, EventArgs e)
{
Div1.InnerHtml = "";
if(HtmlInputCheckBox1.Checked == true)
{
Div1.InnerHtml = "You like basketball. ";
}
if(HtmlInputCheckBox2.Checked == true)
{
Div1.InnerHtml += "You like football. ";
}
if(HtmlInputCheckBox3.Checked == true)
{
Div1.InnerHtml += "You like soccer. ";
}
}
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlInputCheckBox - OnPreRender - C# Example</h3>
<br />
Enter Interests:<p>
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox1"
runat="server"
type="checkbox" checked
value="Basketball"> Basketball
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox2"
runat="server"
type="checkbox"
value="Football"> Football
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox3"
runat="server"
type="checkbox"
value="Soccer"> Soccer
</p>
<p>
<input id="Button1"
runat="server"
type="button"
value="Enter"
onserverclick="Button1_Click"
name="Button1" />
</p>
<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 HtmlInputCheckBox - OnPreRender - Visual Basic Example</title>
<script runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
Div1.InnerHtml = ""
If HtmlInputCheckBox1.Checked = True Then
Div1.InnerHtml = "You like basketball. "
End If
If HtmlInputCheckBox2.Checked = True Then
Div1.InnerHtml += "You like football. "
End If
If HtmlInputCheckBox3.Checked = True Then
Div1.InnerHtml += "You like soccer. "
End If
End Sub
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlInputCheckBox - OnPreRender - Visual Basic Example</h3>
<br />
Enter Interests:<p>
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox1"
runat="server"
type="checkbox" checked
value="Basketball"> Basketball
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox2"
runat="server"
type="checkbox"
value="Football"> Football
<aspSample:CustomHtmlInputCheckBoxOnPreRender
id="HtmlInputCheckBox3"
runat="server"
type="checkbox"
value="Soccer"> Soccer
</p>
<p>
<input id="Button1"
runat="server"
type="button"
value="Enter"
onserverclick="Button1_Click"
name="Button1" />
</p>
<br />
<div id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
ms_positioning="FlowLayout" />
</form>
</body>
</html>
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomHtmlInputCheckBoxOnPreRender : System.Web.UI.HtmlControls.HtmlInputCheckBox
{
protected override void OnPreRender(System.EventArgs e)
{
// Call the base class's OnPreRender method.
base.OnPreRender(e);
// Add a Title attribute to each HtmlInputCheckBox.
this.Attributes.Add("title", "If you like " + this.Value + ", then select this check box.");
}
}
}
Imports System.Web
Imports System.Security.Permissions
Namespace Samples.AspNet.VB.Controls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomHtmlInputCheckBoxOnPreRender
Inherits System.Web.UI.HtmlControls.HtmlInputCheckBox
Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)
' Call the base class's OnPreRender method.
MyBase.OnPreRender(e)
' Add a Title attribute to each HtmlInputCheckBox.
Me.Attributes.Add("title", "If you like " + Me.Value + ", then select this check box.")
End Sub
End Class
End Namespace
Remarks
The OnPreRender method overrides the base OnPreRender method. OnPreRender is used primarily by control developers.
Applies to
.NET
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