ServerValidateEventHandler Delegate
Represents the method that will handle the ServerValidate event of a CustomValidator control.
Assembly: System.Web (in System.Web.dll)
Public Delegate Sub ServerValidateEventHandler ( source As Object, args As ServerValidateEventArgs )
Parameters
- source
-
Type:
System.Object
The source of the event.
- args
-
Type:
System.Web.UI.WebControls.ServerValidateEventArgs
A ServerValidateEventArgs that contains the event data.
Use this delegate to provide custom code that performs validation on the server. Your code needs to validate the Value property of the args parameter passed to the delegate. Store the result of the validation in the IsValid property of the args parameter.
When you create a ServerValidateEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see NIB: Events and Delegates.
For more information about handling events, see NIB: Consuming Events.
The following example demonstrates how to specify and code a handler for a server-side CustomValidator. It displays whether a number entered into a text box is odd or even.
<%@ 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>
<%@ 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 Sub Page_Load(sende As object, e As EventArgs) ' Manually register the event-handling method for the ' ServerValidate event of the CustomValidator control. AddHandler CustomValidator1.ServerValidate, _ AddressOf ServerValidation 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" runat="server"/> <br /> <asp:Button id="Button1" Text="Validate" OnClick="ValidateBtn_OnClick" runat="server"/> </form> </body> </html>
Available since 1.1