I have created a custom server control. So far this control renders some html in the webpage. On submit of the page i need to take the values entered in  the textbox of the server control and call some webservice to validate the input of the user. i don't want to write this code in code behind of the page that this control is used in. I want all the validations to be written in the server control itself and if validation fails, Page.IsValid should be set to false. If the user input value in server control is valid Page.IsValid will be true.

I am trying to achieve is the same functionality as google recaptcha. All user needs to do to use this control is to user the control in the page. user entered value is correct or incorrect is handled in the control itself and in the code behind of the page, there is only Page.IsValid. Here is the page on google that explains this

http://code.google.com/apis/recaptcha/docs/aspnet.html

and i have also used the google recaptcha and it works as expected. I also want to build same kind of functionality for my server control, Please help, if it is possible.