SendMessage Hwnd, WM_HELP, 0, 0

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  18 years ago

  by Edwin Vermeer

  Edwin Vermeer

  Wieringerwaard, The Netherlands, Netherlands

  Joined 18 years ago

  Experts,
  

  
  Some time ago I created an overlay that works on every titelbar for whatever application is active. It has a minimize, maximize, restore and close button that works. What I use for this is:
  

  Code:

  Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
  Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
  PostMessage Hwnd, WMCLOSE, 0, 0

  
  And of course SWSHOWNORMAL,  SWSHOWMAXIMIZED and SWMINIMIZE
  The problem is that the Help button is not working. That is the question mark in the title bar. For a sample right click on your desktop and show the properties.
  

  
  You would think that the code:
  

  Code:

  SendMessage lastHwnd, WM_HELP, 0, 0

  
  should work but it is not. Even the function:
  Code:

  Private Declare Function SetForegroundWindow Lib "user32" (ByVal hwnd As Long) As Long
  SetForegroundWindow Hwnd
  

  
  Does not help.
  

  
  full working code of this can be found here on Planet Source Code. In the menu it's the 'Active titlebar tickertape demo' And in the source code just  look at frmBrowser. It's the code under the question mark that is not working.
  

  
  

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  18 years ago

  by Thushan Fernando

  Thushan Fernando

  Australia :: Melbourne, Australia

  Joined 19 years ago

  according to this:
  

  
  http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/shell/reference/messages/wm_help.asp
  

  
  it should work... but hey if it doesnt then hmmm....
  

  
  the reason is that (thanks to james for pointing this out) that your not parsing the HELPINFO structure:
  

  
  

  Code:

  
  Private Type POINTTYPE
     x As Long
     y As Long
  End Type
  Type HELPINFO
   cbsize As Long
   icontexttype As Long
   ictrlId As Long
   hitemhandle As Long
   dwcontextId As Long
   mousepos As POINTTYPE
  End Type
  Const HELPINFOMENUITEM = 2
  Const HELPINFOWINDOW = 1
  

  
  

  
  the above was converted from:
  

  
  http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/shell/reference/structures/helpinfo.asp
  http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/rectangl_0tiq.asp
  

  
  now try it again... looking at this page:
  

  
  http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/shell/reference/messages/wm_help.asp
  

  
  thanks to the MSDN Library/Platform SDK!
  

  
  

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  18 years ago

  by Edwin Vermeer

  Edwin Vermeer

  Wieringerwaard, The Netherlands, Netherlands

  Joined 18 years ago

  Hmmm.....
  

  
  This does not do what I expected. It's one step away from it.
  Apperently the WMHELP message works on a control and not a window.
  It will show the helpmessage for a control.
  What I want is what happens when you press the question mark in the title bar.
  It's probably a different WM message. I will look around.
  

  
  Thanks
  

  
  

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  18 years ago

  by Thushan Fernando

  Thushan Fernando

  Australia :: Melbourne, Australia

  Joined 19 years ago

  damm i hate when that happens..
  

  
  its not a bug(from Microsoft) from what i can see...
  

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• • Reply

  18 years ago

  by Edwin Vermeer

  Edwin Vermeer

  Wieringerwaard, The Netherlands, Netherlands

  Joined 18 years ago

  Yes, but it's still strange.
  You have the WMClose that is a button in the title bar, the SWMINIMIZE, ...
  So where is the help?
  

  
  

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  18 years ago

  by Edwin Vermeer

  Edwin Vermeer

  Wieringerwaard, The Netherlands, Netherlands

  Joined 18 years ago

  I still can't find the simple solution.
  Maybe this will help but that will take some time:
  Capture the mouse
  change the cursor to the question mark with arrow.
  On mous click send the WM_HELP to whatever is under the mouse.
  

  
  Maybe I can find the window when i subclass a window.
  I will try that first.

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  18 years ago

  by Edwin Vermeer

  Edwin Vermeer

  Wieringerwaard, The Netherlands, Netherlands

  Joined 18 years ago

  Guess it does not work like this.
  When I subclass a window and use the folowing code to filter out some messages
  

  Code:

  
  Const WMNCHITTEST = 132
  If uMsg = WMNCHITTEST Then Exit Sub
  

  
  Const WMMOUSEMOVE = 512
  If uMsg = WMMOUSEMOVE Then Exit Sub
  

  
  Const WMSETCURSOR = 32
  If uMsg = WMSETCURSOR Then Exit Sub
  

  
  Const WMNCMOUSEMOVE = 160
  If uMsg = WMNCMOUSEMOVE Then Exit Sub
  

  
  debug.print uMsg
  

  
  Const WMCAPTURECHANGED = 533
  If uMsg = WMCAPTURECHANGED Then Exit Sub
  

  
  Then you will see that there are no other windows messages.
  

  
  So as I said the only solution is:
  change the cursor
  use SetCapture for keeping track of the mous
  on the mouse click the hwnd of the control below it
  send the WM_Help to the control using the structure pointed out by Thushan.
  

  
  Or does anyone else has an other sugestion?
  

  
  

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