LinkButton.CausesValidation Property

Gets or sets a value indicating whether validation is performed when the LinkButton control is clicked.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

[ThemeableAttribute(false)] 
public virtual bool CausesValidation { get; set; }
/** @property */
public boolean get_CausesValidation ()

/** @property */
public void set_CausesValidation (boolean value)

public function get CausesValidation () : boolean

public function set CausesValidation (value : boolean)

Not applicable.

Property Value

true if validation is performed when the LinkButton control is clicked; otherwise, false. The default value is true.

By default, page validation is performed when a LinkButton control is clicked. Page validation determines whether the input controls associated with a validation control on the page all pass the validation rules specified by the validation control.

You can specify (or determine) whether validation is performed on both the client and the server when a LinkButton control is clicked by using the CausesValidation property. To prevent validation from being performed, set the CausesValidation property to false.

This property is commonly set to false for a Reset or Clear button to prevent validation from being performed when the button is clicked.

When the value of the CausesValidation property is set to true, you can also use the ValidationGroup property to specify the name of the validation group for which the LinkButton control causes validation.

This property cannot be set by themes or style sheet themes. For more information, see ThemeableAttribute and Introduction to ASP.NET Themes.

The following example demonstrates how to use the CausesValidation property to prevent page validation from occurring. Notice how the Validate method activates each validation control independently.

Security noteSecurity Note:

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 (Visual Studio).


<%@ 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 runat="server">
    <title> LinkButton CausesValidation Example </title>
<script runat="server">

      void SubmitButton_Click(Object sender, EventArgs e)
      {
         
         // Determine which button was clicked.
         switch(((LinkButton)sender).ID)
         {

            case "CityQueryButton":

               // Validate only the controls used for the city query.
               CityReqValidator.Validate();

               // Take the appropriate action if the controls pass validation. 
               if (CityReqValidator.IsValid)
               {
                  Message.Text = "You have chosen to run a query for the following city: " + 
                     CityTextBox.Text;
               }

               break;

            case "StateQueryButton":

               // Validate only the controls used for the state query.
               StateReqValidator.Validate();

               // Take the appropriate action if the controls pass validation.
               if (StateReqValidator.IsValid)
               {
                  Message.Text = "You have chosen to run a query for the following state: " + 
                     StateTextBox.Text;
               }

               break;

            default:

               // If the button clicked isn't recognized, erase the message on the page.
               Message.Text = "";

               break;

         }
        
      }

   </script>

</head>

<body>

   <form id="form1" runat="server">

      <h3> LinkButton CausesValidation Example </h3>

      <table border="1" cellpadding="10">
         <tr>
            <td>
               <b>Enter city to query.</b> <br />
               <asp:TextBox ID="CityTextBox" 
                    runat="server"/>
               <asp:RequiredFieldValidator ID="CityReqValidator"
                    ControlToValidate="CityTextBox"
                    ErrorMessage="<br />Please enter a city."
                    Display="Dynamic"
                    EnableClientScript="False"
                    runat="server"/>
            </td>
            <td valign="bottom">
               <asp:LinkButton ID="CityQueryButton"
                    Text="Submit"
                    CausesValidation="False"
                    OnClick="SubmitButton_Click"
                    runat="server"/>
            </td>
         </tr>

         <tr>
            <td>
               <b>Enter state to query.</b> <br />
               <asp:TextBox ID="StateTextBox"  
                    runat="server"/>
               <asp:RequiredFieldValidator ID="StateReqValidator"
                    ControlToValidate="StateTextBox"
                    ErrorMessage="<br />Please enter a state."
                    Display="Dynamic"
                    EnableClientScript="False"
                    runat="server"/>
            </td>
            <td valign="bottom">
               <asp:LinkButton ID="StateQueryButton"
                    Text="Submit"
                    CausesValidation="False"
                    OnClick="SubmitButton_Click"
                    runat="server"/>
            </td>
         </tr>

      </table>

      <br /><br />

      <asp:Label ID="Message"
           runat="Server"/>

   </form>

</body>
</html>

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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