Windows taskbar width and height

[Vag]

Hello.
I like having the windows taskbar on the top of my screen, so sometimes new windows that appear on the top are covered by it, I can't move them and it gets annoying.

I have made a program which can see where the taskbar is and positions itself a little better. For example, if the taskbar is on the top of the screen and the user has selected the program to appear on the top of the screen as well, then I subtract something from Form1.top.
This works perfectly on my machine, as I subtract exactly the taskbar height, but this number may vary in other machines.
I have Windows XP but I have selected the old windows 98 style. The normal XP taskbar is thicker. Or someone could have a bigger taskbar by dragging it...

So the problem is, how can I know the windows taskbar's real height (when it's on top or bottom) and width (when it's left or right of the screen)?

[Thread1]

One way is to use the SystemParametersInfo API function with the SPI_GETWORKAREA value set to get the portion of the screen obscure by the taskbar and then from there you can compute the height of the taskbar.

And the other way is to use the API function.. See sample code below..

Option Explicit

Private Const ABM_GETTASKBARPOS = &H5

Private Type RECT
  Left As Long
  Top As Long
  Right As Long
  Bottom As Long
End Type

Private Type APPBARDATA
  cbSize As Long
  hwnd As Long
  uCallbackMessage As Long
  uEdge As Long
  rc As RECT
  lParam As Long
End Type

Private Declare Function SHAppBarMessage Lib "shell32.dll" (ByVal dwMessage As Long, pData As APPBARDATA) As Long


Private Sub Form_Load()
Dim ABD As APPBARDATA
  
  SHAppBarMessage ABM_GETTASKBARPOS, ABD
  
  MsgBox "Width:" & ABD.rc.Right - ABD.rc.Left & " Height:" & ABD.rc.Bottom - ABD.rc.Top
  
End Sub

I hope that will help you.

[Vag]

Well, it looks it's what I want :-)
Even though I don't have time to test it now, I thank you very much.

[Vag]

I tested the code, it works, but there is something weird...

For example, if the taskbar is on the top of the screen and has its normal size, then (ABD.rc.Bottom - ABD.rc.Top) gives 32 but if I want the window to be placed right under the taskbar, I should set form1.top=450 (or something near that).

I found that if I multiply (ABD.rc.Bottom - ABD.rc.Top) by 14.2, it does the trick, but not all the times!

If the taskbar has been expanded more, I should multiply by a bigger number, maybe 14.9, depending on the taskbar height.

It looks like (ABD.rc.Bottom - ABD.rc.Top) and form1.top are using diferent metric systems, I don't know what to do.

Multiplying by 14.2 works ok if the user hasn't expanded the taskbar much, but I would really like to fix that. Can someone please explain?

[Thread1]

Hi Vag,

It is because they are in different scale. Your app measures in twips by default while the API is in pixels. So you have to scale the API..

Me.Top = Me.ScaleY((ABD.rc.Bottom - ABD.rc.Top), vbPixels, vbTwips)


By the way, the ABD.uEdge specifies the alignment of the taskbar in the screen

Private Const ABE_BOTTOM = 3
Private Const ABE_LEFT = 0
Private Const ABE_RIGHT = 2
Private Const ABE_TOP = 1

[Vag]

I tried it, the window now appears below the taskbar.
It leaves some space though but that's ok, I have to subtract 30.
Perfect, thanks!

[snd2000]

Thanks - exactly what I needed - I had the same issue with scaling as the OP and the replies fixed it.

[DataMiser]

FYI You can use the sysinfo control and access the work area top, left, height and width properties to determine the screen area-the task bar. If you set all of your form properties = the proper workarea property the result will be a properly positioned form that takes full screen - the taskbar area no matter where the task bar is located or what size it may be.

I generally use this for my mdi parent forms.