CustomValidator.OnServerValidate Method (String)
Raises the ServerValidate event for the CustomValidator control.
Assembly: System.Web (in System.Web.dll)
Parameters
- value
-
Type:
System.String
The value to validate.
Return Value
Type: System.Booleantrue if the value specified by the value parameter passes validation; otherwise, false.
The ServerValidate event is raised when validation is performed on the server.
Raising an event invokes the event handler through a delegate. For more information, see NIB: Events and Delegates.
The OnServerValidate method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.
Notes to Inheritors:
When overriding OnServerValidate in a derived class, be sure to call the base class's OnServerValidate method so that registered delegates receive the event.
The following code example demonstrates how to specify and code a handler for a server-side CustomValidator control.
Security Note
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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 xmlns="http://www.w3.org/1999/xhtml" > <head> <title>CustomValidator ServerValidate Example</title> <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-Names="Verdana" Font-Size="10pt" runat="server" AssociatedControlID="Text1" /> <br /> <asp:TextBox id="Text1" runat="server" /> <asp:CustomValidator id="CustomValidator1" ControlToValidate="Text1" Display="Static" ErrorMessage="Not an even number!" ForeColor="green" Font-Names="verdana" Font-Size="10pt" OnServerValidate="ServerValidation" runat="server"/> <br /> <asp:Button id="Button1" Text="Validate" OnClick="ValidateBtn_OnClick" runat="server"/> </form> </body> </html>
Available since 1.1
