The DataGrid 'Edit Data' feature works fine when editing values where there are more than one row. In this case, the results appear in a table and each row's cell can be edited. However, if navigating (via hyperlinks) to a table for which there is only a single row, then the view changes from a table to more of a property sheet view with only two columns: the attributes and values. In this mode, the only thing that allows editing are boolean fields (that appear as checkboxes) and strings. All other numeric values give the following error:

Object of type 'System.String' cannot be converted to type 'System.Int32' (or 'System.Double', etc).