SetWindowsHookEx API -- PLEASE HELP!

[krungkrung]

Hi everyone! Im new to vb.net. I'm currently recoding my vb6.0 codes to vb.net(for upgrading purposes), unfortunately some of the codes dont work/execute the way it executes in vb6.0, though I never get any error. That is, the program runs without error but the function being called dont execute. Can anybody help me figure out this matter??

***HERES WHAT SHOULD THE PROGRAM DO....
message box should always display at the center of the owner form and not at the center of the screen(monitor) upon invoking it.

I used the SetWindowsHookEx API in vb6.0 and it executes perfectly. but when i recoded it in vb.net it doesnt execute the it did in vb6...


[HERES MY CODE IN VB.NET]
by simply calling the code inside button1 click event:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
Call Sys_WindowAdjustment(Me)
MsgBox("THIS IS A TEST")
 
End Sub
 

**** "THIS IS A TEST" message box should always appear at the center of the owner form. even if i move the owner form anywhere in the screen, the msgbox shuld always at the center of it..


HERE'S THE ENTIRE CODE RELATED TO Sys_WindowAdjustment

    Public lngHookProcHandle As Long
 
    'API CONSTANTS
    Public Const GWL_HINSTANCE = (-6)
    Public Const WH_CBT = 5
    Public Const HCBT_ACTIVATE = 5
    Public Const SWP_NOZORDER = &H4
    Public Const SWP_NOSIZE = &H1
    Public Const SWP_NOACTIVATE = &H10
 
 
    Public Declare Function UnhookWindowsHookEx Lib "user32.dll" _
                (ByVal hhk As Long) As Long
    Public Declare Function SetWindowPos Lib "user32" _
                (ByVal HWND As Long, ByVal hWndInsertAfter As Long, ByVal X As Long, ByVal Y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long
    Public Declare Function GetWindowPlacement Lib "user32.dll" _
                (ByVal HWND As Long, ByVal lpwndpl As WINDOWPLACEMENT) As Long
    Public Declare Function GetWindowLong Lib "user32.dll" Alias "GetWindowLongA" _
                (ByVal HWND As Long, ByVal nIndex As Long) As Long
 
    Public Declare Function GetCurrentThreadId Lib "kernel32.dll" () As Long
    Public Declare Function SetWindowsHookEx Lib "user32.dll" Alias "SetWindowsHookExA" _
                (ByVal idHook As Long, ByVal lpfn As Sys_WindowHookProcDelegate, ByVal hMod As Long, ByVal dwThreadId As Long) As Long
 
    Public Delegate Function Sys_WindowHookProcDelegate(ByVal nCode As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
 
    Public Structure WINDOWRECT
        Dim LEFT As Long
        Dim TOP As Long
        Dim RIGHT As Long
        Dim BOTTOM As Long
    End Structure
 
    Public Structure POINTCOORDINATES
        Dim X_POINT As Long
        Dim Y_POINT As Long
    End Structure
 
 
    Public Structure WINDOWPLACEMENT
        Dim length As Long
        Dim Flags As Long
        Dim showCmd As Long
        Dim ptMinPosition As POINTCOORDINATES
        Dim ptMaxPosition As POINTCOORDINATES
        Dim rcNormalPosition As WINDOWRECT
    End Structure
 
    Public sysWindowPlacement As WINDOWPLACEMENT
 
    Public Structure WINDOWCONTAINER
        Dim W_TOP As Double
        Dim W_LEFT As Double
        Dim W_WIDTH As Double
        Dim W_HEIGHT As Double
    End Structure
 
    Public sysWindowContainer As WINDOWCONTAINER
 
 
 
    Public Function Sys_WindowAdjustment(ByVal objOwnerForm As Form) As Long
 
        Dim dlgWinHookDel As Sys_WindowHookProcDelegate
        Dim strErrMsg As String
        Dim strErrNum As String
        Dim strErrorDesc As String
        Dim strErrLocNum As String
        Dim lngInstanceHandle As Long
        Dim lngThreadId As Long
 
        On Error GoTo Sys_WindowAdjustment_Err
 
        strErrMsg = "CommonTools -- Sys_WindowAdjustment"
 
        'Initialize window adjustment to 0
        Sys_WindowAdjustment = 0
        'Get ownerform's top,left,height, width values
        With sysWindowContainer
            .W_TOP = objOwnerForm.Top
            .W_LEFT = objOwnerForm.Left
            .W_HEIGHT = objOwnerForm.Height
            .W_WIDTH = objOwnerForm.Width
        End With
 
        'Get ownerform's instance handle
        lngInstanceHandle = GetWindowLong(objOwnerForm.Handle, GWL_HINSTANCE)
 
        'Get current thread ID
        lngThreadId = GetCurrentThreadId
        'Instantiate new window hook delegate
        dlgWinHookDel = New Sys_WindowHookProcDelegate(AddressOf Sys_WindowHookProc)
        'Set windows hook (set position of window to be loaded)
        lngHookProcHandle = SetWindowsHookEx(WH_CBT, _
                                             dlgWinHookDel, _
                                             lngInstanceHandle, _
                                             lngThreadId)
 
        Sys_WindowAdjustment = lngHookProcHandle
End Function
 
   Public Function Sys_WindowHookProc(ByVal nCode As Long, _
                                       ByVal wParam As Long, _
                                       ByVal lParam As Long) As Long
 
        Dim lngXPos As Long     'Window's Left position
        Dim lngYPos As Long     'Window's Top Position
        Dim dblXPos As Double
        Dim dblYPos As Double
        Dim lngPlacement As Long     'Window Placement
 
        On Error Resume Next
 
        'If window is to be activated
        If nCode = HCBT_ACTIVATE Then
 
            sysWindowPlacement.length = Len(sysWindowPlacement)
            'Get window placement
            lngPlacement = GetWindowPlacement(wParam, sysWindowPlacement)
            'Set Top and Left position of window to be activated
            With sysWindowPlacement.rcNormalPosition
                dblYPos = sysWindowContainer.W_TOP + (sysWindowContainer.W_HEIGHT / 2 - (.BOTTOM - .TOP) * 15 / 2)
                dblXPos = sysWindowContainer.W_LEFT + (sysWindowContainer.W_WIDTH / 2 - (.RIGHT - .LEFT) * 15 / 2)
            End With
 
            'Convert to pixels
            lngXPos = CLng(dblXPos / 15)
            lngYPos = CLng(dblYPos / 15)
 
            'Set window position
            SetWindowPos(wParam, _
                         0, _
                         lngXPos, _
                         lngYPos, _
                         0, _
                         0, _
                         SWP_NOSIZE Or _
                         SWP_NOZORDER Or _
                         SWP_NOACTIVATE)
            'After setting window position, remove window's hook
            UnhookWindowsHookEx(lngHookProcHandle)
        End If
 
        'Set Sys_WindowHookProc to false to continue normal execution
        Sys_WindowHookProc = False
 
    End Function
 

****EVERY TIME THE PROGRAM EXECUTES THE Sys_WindowHookProc FUNCTION IS NEVER EXECUTED OR BEING BY-PASSED...WHAT SHOULD BE THE PROBLEM OF THIS CODE?....I BELIEVE I PRETTY CODED IT WELL(MORE READABLE AND UNDERSTANDABLE I THINK)...BTW I JUST WROTE THIS IN CAPITALS SO THAT VB CODES CAN BE RECOGNIZE OR EMPHASIZE..TNX A LOT.

[Plater]

MsgBox is not .NET code. Try using MessageBox.Show() and going through the overloads to specify who the "owner form" is?

[Curtis Rutland]

Please enclose your posted code in [CODE] [/CODE] tags (See How to Ask a Question).

This makes it easier for our Experts to read and understand it. Failing to do so creates extra work for the moderators, thus wasting resources, otherwise available to answer the members' questions.

Please use [CODE] [/CODE] tags in future.

MODERATOR

[krungkrung]

oh my apology....

hi Plater...I used MessageBox.Show() and it did not make any difference....the message box appeared but its not at the center of the owner form(as what im expecting)....as what ive said..Im new to vb.net. Just started using this like 2 days ago..;-)

[Plater]

Hmm I guess it's not available.
The only other thing I can think of is to make your own custom popup form.
You can either set its start position to "manual" and compute where it goes...
Or you can set TopMost =false (manually in code when you create an instance of it), give its Parent property that of the form you want it centered on, then attempt to set the StartPosition to "CenterParent"

[krungkrung]

tnx for that bright idea Plater...maybe i should try it then...(",)