I have not bound the extended column (A) to the grid. But When navigating in the grid, The exception "Column A does not belong to table X".

There must be an easy way to control and manage the extended properties and properties that are not used with current state of the object. This was the reason why they were not selected. Otherwise, All the properties and extended properties have to be selected in each query. It is not optimal when we have many relations (extended properties from other objects.) to do so.

Note : Extended properties are used to binding purposes.

1. The custom property is an actual field in the table that is expected when updating in which case you would want to add the field to the ExcludeOnUpdates property.
2. You are evaluating the field (referencing the field) when you have not pulled back the field that is used by the custom field
3. Calling the MyBo.Item property to retrieve the vaue from within that item which would cause a recursive error in which case you should be using MyBo.CurrentRow.Item("MyField")

Column 'code' does not belong to table mt_pch_companies.

Because I couldn't select this column. What is the way of managing column and object properties with these conditions ?

Exception :

Column 'ClientAccountName' does not belong to table mt_pch_companies.