Switch between drop-list and drop-down mode

Environment: VC6, NT4 SP3.

switch_list.jpg (5874 bytes)

switch_drop.jpg (4847 bytes)

After reading the article written by Robert Cremer , I realized that his version doesn't correctly draw the blue selection rectangle around the selected item within the combo box. Therefore, I took a different tack in the designing of my version of a class that allows you to programmatically switch a combo box between "drop-list" and "drop-down" mode.

To do this, I create an edit control that simulates the child edit of a real drop-down combo box. The included files have one CComboBox derived class with overrides on OnDropDown and OnCloseUp, and one CEdit derived class that takes care of the up/down arrows used no navigate in the combobox.

The only (let's say) tricky parts are:

  • Making the edit selectable by mouse. I used ::SetWindowPos to put in in the front of the combo in the Z-order
  • Making the combo selectable/not selectable by TAB. ModifyStyle(WS_TABSTOP,0) to remove, ModifyStyle(0,WS_TABSTOP) to add the combo to the tab order list.

Usage

In order to use this class, simply follow these steps:
  • In your dialog, add a drop-list combobox
  • Add a member variable to the dialog of the type CComboBox
  • Modify the dialog's header file so that instead of the newly created combo box variable being declared as a CComboBox, it is declared as a CFineCombo.
  • Now, update your dialog's code to include calls to SwitchToDrop(TRUE) (switches to drop-down) or SwitchToDrop(FALSE) (switches to drop-list) where appropriate.
  • Delete the ClassWizard (.clw) file.
  • Rebuild the ClassWizard file so that it contains the newly added CFineCombo class.

Downloads

Download demo project - 20 Kb
Download source - 3 Kb


Comments

  • highlight the characters in Drop down mode

    Posted by Legacy on 08/12/1999 12:00am

    Originally posted by: Ian

    Hi Bruno,

    Your program is really helpful to me. Thanks.

    I'd like to highlight the characters (set by SetWindowText(str)) right away after switching to Drop down mode. However I couldn't fig it out after spending several hours. Your help will be much appreciated.

    Ian

    Reply
  • no CBN_SELCHANGE message?

    Posted by Legacy on 08/06/1999 12:00am

    Originally posted by: Thomas Scherer

    Hey Bruno
    
    if the "CFineEdit" is active, the "parent dialog window" will be not notified about selection changing with "up/down key". I changed your code like this..

    void CFineEdit::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
    {
    ..
    switch( .. ) {
    case DOWNARROW and UPARROW:
    ..
    GetParent()->SendMessage(WM_COMMAND,
    MAKEWPARAM(m_combo->GetDlgCtrlID(), CBN_SELCHANGE),
    (LPARAM)m_combo->m_hWnd);
    break;
    }
    ..
    }

    Insert the "SendMessage.." line at both locations (Down / Up) and the user will be notified!

    Thomas Scherer

    Reply
  • How to rebuild CLW file?

    Posted by Legacy on 07/28/1999 12:00am

    Originally posted by: Tom Stepka

    Exactly how does one go about rebuilding a deleted CLW file?

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: May 11, 2015 @ 1:00 p.m. ET / 10:00 a.m. PT One of the languages that have always been supported with the Intel® RealSense™ SDK (Software Developer Kit) is JavaScript, specifically so that web-enabled apps could be created. Come hear from Intel Expert Bob Duffy as he reviews his own little "space shooting" game where the orientation of your face controls the aiming reticle to help teach developers how to write apps and games in JavaScript that can use facial and gesture …

  • There has been growing buzz about DevOps. DevOps is a methodology that unites the often separate functions of software development (Dev) and production and operations (Ops) into a single, integrated, and continuous process. DevOps is about breaking down the barriers between Dev and Ops. It leverages people, processes, and technology to stimulate collaboration and innovation across the entire software development and release process. Dev and Ops should always be part of an integrated process, but that's not …

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date