I have a UserForm which amongst other controls contains a combo box.
The combo box is populated by a dynamic list . At first it was possible to use the dropdown list as a way of verifying data entry. Now however the list is 1200 items long so this is not practicable and the manual entry aspect of the combo box is frequently used. Mistakes occur and cause problems later on in the application.

In use, after the Userform is completed subsequent action is started by a command button so I think that this is the place to institute the check. With the userform being re-presented partially completed if there is a wrong entry in the combo box, or the normal action continuing if there is no problem. I have not been able to achieve this in code and I would greatly appreciate some help in doing so.
I have also tried to use the change event of the combo box without success. This was particularly difficult because sometimes the Combo box is filled from a database, rather than manually.
Looking forward toyour ideas
LoftySuth