SetParent problem [resolved]

[Fox]

Hello everyone.

I'm working on a windows extension that adds a "Minimize to tray" button to each window. I got everything to work but there's one problem remaining:

For the button I use a UserControl because of several reasons. However I found out when using SetParent( handle, 0 ) a tab in the taskbar appears. Try it by creating a new project, adding a PictureBox and using SetParent with 0 as parent handle.

Now the question is how can I avoid this taskbar tab? Thanks for hints,

Fox

[Disiance]

You could use the SetParent as you are, then SetWindowAttributes (I think that's the right API) and tell the object not to display in the task bar.

[Fox]

Yes I already tried this but it doesn't work. The code to hide the taskbar button works on other windows but not on the one I changed the parent to 0...

[Disiance]

have you tried setting the desktop winodw as the parent?

[Fox]

Yes, this also creates one more tab in the taskbar...

[Megatron]

Apply the WS_EX_TOOLWINDOW extended style to your window. This will trick windows into thinking it's a tool window, and thus remove it from the task bar.

Here's a quick example

Private Declare Function GetWindowLong Lib "user32.dll" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32.dll" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function SetParent Lib "user32.dll" (ByVal hWndChild As Long, ByVal hWndNewParent As Long) As Long
Private Const GWL_EXSTYLE = -20
Private Const WS_EX_TOOLWINDOW As Long = &H80&
 
Private Sub Command1_Click()
        
    ' make the picturebox a top-level parent window
    
    Dim lstyle As Long
    
    'apply the tool window extended style
    lstyle = GetWindowLong(Picture1.hwnd, GWL_EXSTYLE)
    lstyle = lstyle Or WS_EX_TOOLWINDOW
    SetWindowLong Picture1.hwnd, GWL_EXSTYLE, lstyle
    
    SetParent Picture1.hwnd, 0
    
End Sub
 
Private Sub Picture1_Click()
    'close the form
    Unload Me
End Sub

[Fox]

Thanks alot, that works

[Disiance]

When you finish this program Fox could you please post it for download? This type of project has been on the back of my mind for months now but I adhore subclassing.

[Fox]

Of course. It's not just a minimize to tray, it's a whole windows manager suite (thus called "WinMan"). You can show/hide/rename/set alpha/whatever on each window. Also you can apply bots to automate those actions (eg. "Set ICQ's alpha to 20% when it's running").

This is the 2nd edition btw, the original code was written in 2001 - even it's crappy coded ever since, it's one of the most-used tools I got.