MutuallyExclusiveCheckBox is an ASP.NET AJAX extender that can be attached to any ASP.NET
CheckBox control. By adding a number of checkboxes to the same "Key", only one checkbox
with the specified key can be checked at a time. This extender is useful when a number of
choices are available but only one can be chosen, similar to a radio button. The use of
checkboxes however allows you to choose to uncheck a value which is not possible normally
with radio buttons. This also provides a more consistent and expected interface than using
The control above is initialized with this code.