LinkButton.CausesValidation Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

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.

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

public:
 property bool CausesValidation { bool get(); void set(bool value); };

public:
 virtual property bool CausesValidation { bool get(); void set(bool value); };

[System.ComponentModel.Bindable(false)]
public bool CausesValidation { get; set; }

[System.Web.UI.Themeable(false)]
public virtual bool CausesValidation { get; set; }

[<System.ComponentModel.Bindable(false)>]
member this.CausesValidation : bool with get, set

[<System.Web.UI.Themeable(false)>]
member this.CausesValidation : bool with get, set

Public Property CausesValidation As Boolean

Public Overridable Property CausesValidation As Boolean

Property Value

Boolean

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

Implements

CausesValidation

Attributes: BindableAttribute ThemeableAttribute

Examples

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.

Important

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="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>


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

      Sub SubmitButton_Click(sender As Object, e As EventArgs)
         
         ' Determine which button was clicked.
         Select Case (CType(sender, LinkButton)).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 Then
           
                  Message.Text = "You have chosen to run a query for the following city: " & _ 
                     CityTextBox.Text
               
               End If

            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 Then
               
                  Message.Text = "You have chosen to run a query for the following state: " & _ 
                     StateTextBox.Text
               
               End If

            Case Else

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

         End Select
        
      End Sub

   </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>

Remarks

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 ASP.NET Themes and Skins.

Applies to

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