ComboBox Height

[BudDurland]

On my current project, I have one dialog with a combobox that contains many items.  When run the combox box list goes the entire height of the screen -- clipping off the last item in the list.  I search the forum, and tried to limit the height of the CB like so:

Code Select Expand

  FF_CONTROL_GETSIZE HWND_DOWNTIME_DTREASON, lWidth, lHeight
  SETWINDOWPOS HWND_DOWNTIME_DTREASON, 0, 0, 0, lWidth, (lHeight / 2), %SWP_NOMOVE OR %SWP_SHOWWINDOW OR %SWP_NOZORDER

But that seems to have no effect.  I've tried both %CBS_DROPDOWN and %CBS_DROPDOWNLIST, as well as changing %CBS_NOINTREGALHEIGHT.  I've also noticed that in the properties of the control, FireFly keeps resetting "Height" to 35 after a compile (or almost any other change to the form)

What else can I try?

[BudDurland]

Correction -- setting NOINTREGALHEIGHT trims the size, but does it too much.. With tat setting, the display is about 5 lines (16 point font, 'cuase we're using touch screens).

[TechSupport]

Hi Bud,

ComboBoxes are a strange animal. The height of the control is dictated by the selected font. From my tests, you can control the height of the dropdown list by setting the CBS_NOINTEGRALHEIGHT and then adjusting the height in the CBN_DROPDOWN.

Code Select Expand


'------------------------------------------------------------------------------------------------------------------------
Function FORM1_WM_CREATE ( _
                         hWndForm As Dword, _  ' handle of Form
                         ByVal UserData As Long _  'optional user defined Long value
                         ) As Long

   Local y As Long
   
   For y = 1 To 100
      FF_ComboBox_AddString HWND_FORM1_COMBO1, "MyString" & Str$(y)
   Next
   
End Function



'------------------------------------------------------------------------------------------------------------------------
Function FORM1_COMBO1_CBN_DROPDOWN ( _
                                   ControlIndex  As Long,  _  ' index in Control Array
                                   hWndForm      As Dword, _  ' handle of Form
                                   hWndControl   As Dword, _  ' handle of Control
                                   idComboBox    As Dword  _  ' identifier of combobox
                                   ) As Long

   Local nWidth  As Long
   Local nHeight As Long
   Local rc      As Rect

   GetWindowRect HWND_FORM1_COMBO1, rc
   nWidth  = rc.nRight - rc.nLeft
   nHeight = (rc.nBottom - rc.nTop) / 2
   SetWindowPos HWND_FORM1_COMBO1, 0, 0, 0, nWidth, nHeight, %SWP_NOZORDER Or %SWP_NOMOVE

End Function



[BudDurland]

Grrr.  This is maddening; I added the code to the "_DROPDOWN" routine and it seems to have no effect.  I tried different divisors (rc.nBottom - rc.nTop) /3,  /4, etc), with no appreciable difference in the list.

I may search around of a custom control for this.  The app is run on touch screens; it would be cool if the vertical scroll bar was much wider.

[TechSupport]

That is strange. My tests seemed to work. Make sure that you set the CBS_NOINTEGRALHEIGHT style for the combobox. Maybe you're also manipulating the combobox in the Form's CUSTOM event handler?

Try creating a sample project with just my code above to see if you can at least see the behaviour that I'm seeing.

Weird.

[BudDurland]

I have come to the conclusion that windows has a mind of it's own.  GetWindowRec and SetWindowPos are what I need to solve the problem at hand, but the behavior took a while to figure out

I made a new project with just the code you posted.  I confirmed that NOT checking CBS_INTREGALHEIGHT results is a way long drop-down.  I re-checked that setting, then ran the program.  The area of the drop-down list was shortened, and of course the number of lines displayed was a function of that area.  I tried changing how nHeight was computed (/2, /3, /4,) and the area did not change.  Then I got silly, and tried (* 2).  Now the drop-down area was only 1 line high!  Using (* 10) made the drop down area much bigger, but not as big as when CBS_NOINTREGALHEIGHT wasn't set.

Then, I experimented with hard-coding the value (100, 200, 300, 400, etc), and the drop-down area changed pretty much as expected.  For my project, I can live with hard-coding the value; the behavior just strikes me as strange