Adding items to QComboBox

[d_stranz]

I can open it by calling showPopup()

showPopup() is probably a nonmodal dialog-type method; that is, the popup widget contains its own event loop to monitor user selections and while it is visible it doesn't respond to changes in the combo box contents. If you want to change this behavior, you may be able to derive from QComboBox and override showPopup() . I don't think it will be very easy to do that and maintain the same behavior that the combobox popup normally has. Its implementation probably depends on there being a fixed number of items in the list, so if you are modifying the list while the user is trying to make a selection, then the indexing has to be carefully managed to avoid returning the wrong index values when a selection is made.

[buster]

It is strange that QComboBox doesn't implement this behaviour, as it would be very useful. Perhaps it will be included in Qt 6?

[d_stranz]

It is strange that QComboBox doesn't implement this behaviour

I think the behaviour you propose is strange.

The purpose of the popup is to allow the user to make a selection from the items in the combobox's list, not to display the list of items in a dynamic way. How is the user supposed to make a choice when the list she is seeing is constantly changing underneath her mouse? This would be even worse if the combobox had sorted contents - the contents would keep rearranging themselves, making it impossible to choose the one you want. More often than not, you would probably end up with the wrong one because the list changed underneath you and you didn't notice.

And think how frustrating it would be if each time you opened the popup box, you saw a different list of items. It would be one thing if -you- did something which caused the list to change (like choose a different search term) versus the list changing because the program did it without any input from you.

[buster]

Maybe I did not explain properly what I meant. What I am after is behaviour somewhat similar to that of Wikipedia, where the list opens up as soon as one starts to type text (the lineedit under the cursor do not change) and then the selection in the drop down list is dynamically altered as one types. What's in the list will of cause have be inserted from code. That saves the user from having to manually open the drop-list.

[d_stranz]

Ah, then what you want is not a plain QComboBox, but a QComboBox or QLineEdit containing a QCompleter in PopupCompletion mode.