When can you use IForm.addHiddenValue or IForm.addDeferredRunnables

[Muljadi Sulistio <ms...@gmail.com>]

Hi,

I'm looking for some info on when you can call the method of
IForm.addHiddenValue and IForm.addDeferredRunnables.  Looking at the
Tapestry 4 source code, Form.java implements IForm.  The implementation
method for addHiddenValue and addDeferredRunnables depended on FormSupport
instance (_formSupport).  However, _formSupport is only instantiated during
Form's renderComponent.  Calling addHIddenValue or addDeferredRunnables
outside renderComponent cycle will throw NullPointerException.
The reason I'm calling addHiddenValue is to add several hidden fields into
every form that'll be generated by many pages, so it's not practical to do
that within .html by adding @Hidden components.

Thanks.