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CustomValidator.ClientValidationFunction Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Gets or sets the name of the custom client-side script function used for validation.

public:
 property System::String ^ ClientValidationFunction { System::String ^ get(); void set(System::String ^ value); };
public string ClientValidationFunction { get; set; }
[System.Web.UI.Themeable(false)]
public string ClientValidationFunction { get; set; }
member this.ClientValidationFunction : string with get, set
[<System.Web.UI.Themeable(false)>]
member this.ClientValidationFunction : string with get, set
Public Property ClientValidationFunction As String

Property Value

String

The name of the custom client script function used for validation. The default value is Empty, which indicates that this property is not set. The function name should not include any parentheses or parameters.

Attributes
ThemeableAttribute

Examples

The following code example demonstrates how to use the ClientValidationFunction property to specify the name of the function that performs client-side validation. The validation function checks for even numbers. For a description of the function parameters, see the Remarks section of CustomValidator.

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" %>

<html>
<head>

   <script runat="server">

      void ValidateBtn_OnClick(object sender, EventArgs e) 
      { 
         // Display whether the page passed validation.
         if (Page.IsValid) 
         {
            Message.Text = "Page is valid.";
         }

         else 
         {
            Message.Text = "Page is not valid!";
         }
      }

      void ServerValidation(object source, ServerValidateEventArgs args)
      {
         try 
         {
            // Test whether the value entered into the text box is even.
            int i = int.Parse(args.Value);
            args.IsValid = ((i%2) == 0);
         }

         catch(Exception ex)
         {
            args.IsValid = false;
         }
      }
       
   </script>    

</head>
<body>

   <form id="Form1" runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>

      <asp:Label id="Message"  
           Text="Enter an even number:" 
           Font-Name="Verdana" 
           Font-Size="10pt" 
           runat="server"/>

      <p>

      <asp:TextBox id="Text1" 
           runat="server" />
    
        

      <asp:CustomValidator id="CustomValidator1"
           ControlToValidate="Text1"
           ClientValidationFunction="ClientValidate"
           OnServerValidate="ServerValidation"
           Display="Static"
           ErrorMessage="Not an even number!"
           ForeColor="green"
           Font-Name="verdana" 
           Font-Size="10pt"
           runat="server"/>

      <p>
 
      <asp:Button id="Button1"
           Text="Validate" 
           OnClick="ValidateBtn_OnClick" 
           runat="server"/>

   </form>
</body>
</html>

<script language="javascript"> 
   function ClientValidate(source, arguments)
   {
        if (arguments.Value % 2 == 0 ){
            arguments.IsValid = true;
        } else {
            arguments.IsValid = false;
        }
   }
</script>

<%@ Page Language="VB" AutoEventWireup="True" %>

<html>
<head>

   <script runat="server">

      Sub ValidateBtn_OnClick(sender As Object, e As EventArgs) 
           ' Display whether the page passed validation.
           If Page.IsValid Then
               Message.Text = "Page is valid."
           Else
               Message.Text = "Page is not valid!"
           End If
       End Sub

      Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
           Try
               ' Test whether the value entered into the text box is even.
               Dim num As Integer = Integer.Parse(args.Value)
               args.IsValid = ((num Mod 2) = 0)
           Catch ex As Exception
               args.IsValid = False
           End Try
       End Sub

   </script>      

</head>
<body>

   <form id="Form1" runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>

      <asp:Label id="Message"  
           Text="Enter an even number:" 
           Font-Name="Verdana" 
           Font-Size="10pt" 
           runat="server"/>

      <p>

      <asp:TextBox id="Text1" 
           runat="server" />
    
        

      <asp:CustomValidator id="CustomValidator1"
           ControlToValidate="Text1"
           ClientValidationFunction="ClientValidate"
           OnServerValidate="ServerValidation"
           Display="Static"
           ErrorMessage="Not an even number!"
           ForeColor="green"
           Font-Name="verdana" 
           Font-Size="10pt"
           runat="server"/>

      <p>
 
      <asp:Button id="Button1"
           Text="Validate" 
           OnClick="ValidateBtn_OnClick" 
           runat="server"/>

   </form>
  
</body>
</html>

<script language="javascript">
   function ClientValidate(source, arguments)
   {
        if (arguments.Value % 2 == 0 ){
            arguments.IsValid = true;
        } else {
            arguments.IsValid = false;
        }
   }
</script>

Remarks

Set this property to the name of the function that performs the client-side validation.

Because the client validation function runs on the target browser, the function must be written using a scripting language supported by the browser, such as JScript or VBScript.

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

Applies to

See also