Creating a new TypeConverter for asp.net controls

[google]

Hi

I want to create a TypeConverter derived from ControlIdConverter that
lists controls on a WebForm filtered so it only shows specific types,
e.g. just TextBoxes. I have looked at the code for ControlIDConverter
and overriden the FilterControl method.

This didn't work and on further investigation it seems I'm always
getting null passed in the context parameter of GetStandardValues.
This therefore goes no further and returns null as the list. Does
anyone know why null is being passed? I was expecting an
IDesignerHost, i.e. the WebForm designer so I could get the controls
on it.

Thanks
Russell Mason