Represents a label control, which displays text on a Web page.
<ControlValuePropertyAttribute("Text")> _ <AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _ <AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _ Public Class Label _ Inherits WebControl _ Implements ITextControl
Dim instance As Label
[ControlValuePropertyAttribute("Text")] [AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)] [AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)] public class Label : WebControl, ITextControl
[ControlValuePropertyAttribute(L"Text")] [AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)] [AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)] public ref class Label : public WebControl, ITextControl
public class Label extends WebControl implements ITextControl
<asp:Label />
Use the Label control to display text in a set location on the page. Unlike static text, you can customize the displayed text through the Text property.
You can also use the Literal and PlaceHolder controls to display text on the Web Forms page. However, unlike the Label control, these controls do not render any additional tags.
This control can be used to display user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.
The markup rendered by default for this control might not conform to accessibility standards such as the Web Content Accessibility Guidelines 1.0 (WCAG) priority 1 guidelines. For details about accessibility support for this control, see ASP.NET Controls and Accessibility.
The following example demonstrates how to create a Label control on a Web page.
The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. This code sample must be copied into an empty text file that has an .aspx extension. For more information on the ASP.NET Web page code model, see ASP.NET Web Page Code Model.
This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.
<%@ 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 > <head> <title>Label Example</title> <script language="VB" runat="server"> Sub Button_Click(Sender As Object, e As EventArgs) Label1.Text = Server.HtmlEncode(Text1.Text) End Sub </script> </head> <body> <form id="Form1" runat="server"> <h3>Label Example</h3> <asp:Label id="Label1" Text="Label Control" runat="server"/> <p> <asp:TextBox id="Text1" Text="Copy this text to the label" Width="200px" runat="server" /> <asp:Button id="Button1" Text="Copy" OnClick="Button_Click" runat="server"/> </p> </form> </body> </html>
<%@ 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 > <head> <title>Label Example</title> <script language="C#" runat="server"> void Button_Click(Object Sender, EventArgs e) { Label1.Text = Server.HtmlEncode(Text1.Text); } </script> </head> <body> <form id="Form1" runat="server"> <h3>Label Example</h3> <asp:Label id="Label1" Text="Label Control" runat="server"/> <p> <asp:TextBox id="Text1" Text="Copy this text to the label" Width="200px" runat="server" /> <asp:Button id="Button1" Text="Copy" OnClick="Button_Click" runat="server"/> </p> </form> </body> </html>
for operating in a hosted environment. Demand value: LinkDemand; Permission value: Minimal.
for operating in a hosted environment. Demand value: InheritanceDemand; Permission value: Minimal.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The documentation is badly worded with regards to security.
It states "This control can be used to display user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements.".
ASP.NET validation will NOT help you here - only input is validated, not the rendered output of the Label control. It makes it seem as though you're safe including user-generated content in this control.
The contents of an <asp:Label> control are not "HTML Encoded" - if the control is used to display user-generated content (databound or otherwise) without first HTML Encoding it, the page has a serious security problem. Use <asp:Literal Mode="Encode"> instead, if possible.