Solved

How to disable ComboBox automatic scrolling?

Posted on 2000-03-26
9
499 Views
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!
0
Comment
Question by:si124
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 4
9 Comments
 
LVL 1

Accepted Solution

by:
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...
0
 

Author Comment

by:si124
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?

Thanks!
0
 
LVL 1

Expert Comment

by:yarond
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:
::PostMessage(m_Combo.m_hWnd,CB_SETTOPINDEX,0,0);
or:
m_Combo.PostMessage(CB_SETTOPINDEX,0,0);
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.
0
Get proactive database performance tuning online

At Percona’s web store you can order full Percona Database Performance Audit in minutes. Find out the health of your database, and how to improve it. Pay online with a credit card. Improve your database performance now!

 

Author Comment

by:si124
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!

Thanks!



0
 

Author Comment

by:si124
ID: 2663812
I have to repair myself. I meant Post WM_USER+1 message!
0
 
LVL 1

Expert Comment

by:yarond
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?
0
 

Author Comment

by:si124
ID: 2663990
My header control is child window of ListBox. When I use SetTopIndex, windows is scrolled so header control disappears from the view.
0
 
LVL 1

Expert Comment

by:yarond
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.
0
 

Author Comment

by:si124
ID: 2665147
In any case thank you very very much for your help!!!!!
0

Featured Post

Moving data to the cloud? Find out if you’re ready

Before moving to the cloud, it is important to carefully define your db needs, plan for the migration & understand prod. environment. This wp explains how to define what you need from a cloud provider, plan for the migration & what putting a cloud solution into practice entails.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction: Finishing the grid – keyboard support for arrow keys to manoeuvre, entering the numbers.  The PreTranslateMessage function is to be used to intercept and respond to keyboard events. Continuing from the fourth article about sudoku. …
Introduction: Dialogs (2) modeless dialog and a worker thread.  Handling data shared between threads.  Recursive functions. Continuing from the tenth article about sudoku.   Last article we worked with a modal dialog to help maintain informat…
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Add bar graphs to Access queries using Unicode block characters. Graphs appear on every record in the color you want. Give life to numbers. Hopes this gives you ideas on visualizing your data in new ways ~ Create a calculated field in a query: …

635 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question