If you are using databinding, it is going to be difficult to remove unwanted entries … you will most likely want to use unbound comboboxes and manually read the database on the 1st Combobox.SelectedValueChanged event.
When you read the database, exclude the rows you do not want. Then you can add the items into Combobox #2.
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solved value selected in first combo box should not appear in second combobox dropdown list [closed]