an email text control. a control like a text box but that filters out the invalid characters that cannot be used in an email address. This control could be separated in 3 parts: part1@part2.part3 When the user hits the dot "." just before part3, a autocomplete feature can make it easier (faster) to select a frequently used prefex (like .com, .net, .org, etc...). This feature can be customized by the developer. The developer can turn it on or off. He can also make an own autocomplete list and eventually restrict to a list of suffixes. Also when you want the user to type in an email address with a fix part 2 and part 3, the developer could customize it like this (e.g. when you want the user to enter only email addresses of @gmail.com, the developer can do this by design. The three parts in the email address are required in order to have a valid email address. As an extra feature the control can have a "IsValid()"-method that can be used by the developer to quickly check whether the email address is valid. Server-side as well as client-side API make sense....