Listing 1

'This Handler implements server side validation logic for the
'V_CityFieldCustomValidator control
Private Sub V_CityFieldCustomValidator_ServerValidate(ByVal source As
Object, ByVAl args As System.Web.UI.WebControls.ServerValidat
eEventArgs) _
Handles V_CityFieldCustomValidator.ServerValidate
'get the value to validate
Dim value As String = Me.V_CityFieldCustomValidator.
GetValueToValidate()
If (value <> "Mountain View")) Then
Me.V_CityFieldCustomValidator.ErrorMessage = "Please
move to Mountain View."
args.IsValid = False
End If
End Sub