asp.net, append dinamically options to <asp:dropdown>

[delfion]

Hi.

I have an <asp:dropdown> control to which I add items on the client, when the
page is posted back I get this error message.
Invalid postback or callback argument.
Event validation is enabled using <pages enableEventValidation="true"/>
in configuration or <%@ Page EnableEventValidation="true" %> in a page.
For security purposes, this feature verifies that arguments to postback or
callback events originate
from the server control that originally rendered them.
If the data is valid and expected, use the
ClientScriptManager.RegisterForEventValidation
method in order to register the postback or callback data for validation
setting enableEventValidation=false, this does work.
But, i don't want to disable this for security purposes.
how can i use ClientScriptManager.RegisterForEventValidation to disable
EventValidation in my control, instead of turning off event
validation to solve my problem.
thanks for any help