How to disable ComboBox automatic scrolling?

Posted on 2000-03-26
Last Modified: 2013-11-20
I have class MyComboBox. When I select an item from a ListBox, ComboBox is scrolled automatically that selected item is the first on ListBox. How could I disable it?
I tried to do it in OnDropDown, OnLButtonDown in OnClouseUp. Always without success!
I would like to control scrolling by my code!

Thanks all!
Question by:si124
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Accepted Solution

yarond earned 100 total points
ID: 2660165
Well, it's not very elegant, but it will work.
The combobox scrolls the drop-down listbox to the selected item. So what you can do is on the OnDropDown use SetCurSel(-1) which will clear the selection.
However, if you want the selected item to remain selected when you close the drop-down without selecting a different one, before using SetCurSel(-1) use GetCurSel() and keep the return value, and then on OnCloseUp check if GetCurSel()==CB_ERR, and if so (no new item was selected) use SetCurSel(m_PrevSelection).
It will also work properly on the first run because CB_ERR==-1 so if nothing was selected no harm is done. Although it would be much nice to search for this condition on the OnDropDown and not count on it...

Author Comment

ID: 2661688
Thank you very much for your help.
I managed to control scrolling by myself.

I would like to leave selected text in EditBox on DropDown. In this case EditBox is empty (unusal).
Is it possible to fix it?


Expert Comment

ID: 2663534
I found a totally different solution, which is IMHO much better, and answers all your requirements (that I know of).
In the OnDropDown, assuming you have a CComboBox control named m_Combo, use either:
If you use PostMessage and not SendMessage it gets processed only after the dropdown operation is finished, and so it scrolls to the top position.
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Author Comment

ID: 2663810
I used this option before!!!
I send my own WM_USER+1 message and in it I scroll down ListBox to right position.
I can't use SetTopIndex because I have header control on the top of ListBox, so I have to leave it on the top!
Your last solution was OK, except the problem of empty EditBox!
Is there any other possibility to solve my problem!



Author Comment

ID: 2663812
I have to repair myself. I meant Post WM_USER+1 message!

Expert Comment

ID: 2663881
One rather ugly option would be to put a different editbox on top of the combobox's editbox, and in OnDropDown, copying the selected item to it, making it visible, and only then clearing the selection.
But I don't exactly understand how does the header control prevent you from using SetTopIndex. Where exactly is the header control placed, and what happens to it when you use SetTopIndex?

Author Comment

ID: 2663990
My header control is child window of ListBox. When I use SetTopIndex, windows is scrolled so header control disappears from the view.

Expert Comment

ID: 2664683
I can't think of a better solution for you right now. I'll withdraw my answer so someone else might be able to help you.

Author Comment

ID: 2665147
In any case thank you very very much for your help!!!!!

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