While changing the DataSource in the ComboBox cell, a null reference exception is raised. This is because the database is updated and then refreshed after you pick a value from a ComboBox cell by using the RecordValueChanged event. The newly edited value is not committed while the database updates. So, when you try to click on the next row, the RecordValueChanged event refreshes the database before the ComboBox commits the new value into the underlying database.
Figure 1: Null reference exception
This can be solved by calling the EndEdit() in the TableControlCurrentCellCloseDropDown event. Refer to the following code example.
This page will automatically be redirected to the sign-in page in 10 seconds.