CheckBoxList.Render(HtmlTextWriter) Method
Definition
Important
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Displays the CheckBoxList on the client.
protected:
override void Render(System::Web::UI::HtmlTextWriter ^ writer);protected public:
override void Render(System::Web::UI::HtmlTextWriter ^ writer);protected override void Render(System.Web.UI.HtmlTextWriter writer);protected internal override void Render(System.Web.UI.HtmlTextWriter writer);override this.Render : System.Web.UI.HtmlTextWriter -> unitProtected Overrides Sub Render (writer As HtmlTextWriter)Protected Friend Overrides Sub Render (writer As HtmlTextWriter)- writer
- HtmlTextWriter
A HtmlTextWriter that contains the output stream for rendering on the client.
The following code example demonstrates how to override the Render method in a custom server control so that the CheckBoxList always displays an image.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!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 CheckBoxList - Render - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom CheckBoxList - Render - C# Example</h3>
<aspSample:CustomCheckBoxListRender
id="CheckBoxList1" runat="server">
<asp:ListItem Selected="True">Item 1</asp:ListItem>
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
<asp:ListItem>Item 4</asp:ListItem>
<asp:ListItem>Item 5</asp:ListItem>
<asp:ListItem>Item 6</asp:ListItem>
</aspSample:CustomCheckBoxListRender>
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page language="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 CheckBoxList - Render - VB.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom CheckBoxList - Render - VB.NET Example</h3>
<aspSample:CustomCheckBoxListRender id="CheckBoxList" runat="server"
RepeatLayout="Table" RepeatColumns="2" CellSpacing="3" CellPadding="3">
<asp:ListItem Selected="True">Item 1</asp:ListItem>
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
<asp:ListItem>Item 4</asp:ListItem>
<asp:ListItem>Item 5</asp:ListItem>
<asp:ListItem>Item 6</asp:ListItem>
</aspSample:CustomCheckBoxListRender>
</form>
</body>
</html>
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomCheckBoxListRender : System.Web.UI.WebControls.CheckBoxList
{
protected override void Render(System.Web.UI.HtmlTextWriter writer)
{
// Create and render a new Image Web control.
System.Web.UI.WebControls.Image image = new System.Web.UI.WebControls.Image();
image.ID = "Image1";
image.ImageUrl = "image.jpg";
image.AlternateText = "Image for CheckBoxList1.";
image.RenderControl(writer);
// Call the base class's Render method.
base.Render(writer);
}
}
}
Imports System.Web
Imports System.Security.Permissions
Namespace Samples.AspNet.VB.Controls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomCheckBoxListRender
Inherits System.Web.UI.WebControls.CheckBoxList
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
' Create and render a new Image Web control.
Dim image As New System.Web.UI.WebControls.Image
image.ID = "Image1"
image.ImageUrl = "image.jpg"
image.AlternateText = "Image for CheckBoxList1."
image.RenderControl(writer)
' Call the base class's Render method.
MyBase.Render(writer)
End Sub
End Class
End Namespace
The Render method is used primarily by control developers in custom controls that derive from the CheckBoxList class.
The Render implementation for a CheckBoxList control initializes a RepeatInfo object for the list, and calls the RenderRepeater method, which in turn uses the RenderItem method to render individual check box list items.
