There seems to be a general problem where mmGridView.BindBack() causes unhandled exceptions with invalid (mostly null) data BEFORE the business rule check.

It seems that the solution is either:

1) subclass mmGridView, override BindBack(), and

a) do some instance code for each table/gridview's data particularities. Horrible.

or b) have some general solution where BindBack() checks nullable and returns some obviously invalid token to be checked in the business rules later.

For example, a blank integer where 0 and -1 are valid entries might get set to -999999 as a "set me to DBNull flag" and just hope that value's never a valid entry. Horrible.

or 2) manually do data and business rule checks and cancel out before the call to

        // Save the DataSet (the GridView automatically binds back)
        mmSaveDataResult saveResult = this.Save(this.oManualCountSheet, dsManualCountSheet);

(But this still wouldn't handle the case where data is supposed to be nullable.)

Suggestions please! Thanks!