mono/mono — pull request #1132 by mattleibow (2014-06-27 11:44:22+00:00)
Title: [system.data] BUGFIX: fixes issue with expression columns and IsNull:

- bugzilla.xamarin.com issue 20925 (https://bugzilla.xamarin.com/show_bug.cgi?id=20925)
- if an expression column was added after there were rows, and then IsNull is called, the result is incorrect (it will always be true)