Add WHERE Clause Dialog Box Doesn't Support Object Source?

[Jonathan Wood]

When configuring a data source for the GridView, I can access the Add WHERE
Clause dialog box, which allows me to filter the results based on a
particular column's relationship to any of a number of different data
sources (cookies, control, form, etc.).

However, what I'd really like to do is tie it to a static property of one of
my application's classes.

Does anyone know why this option does not appear to be supported, or if
there's any workaround?

Thanks.