win32- hook: why i can't change anything?

[Cambalinho]

i have these functions for show a messagebox:

int GetWindowString(HWND hwnd, std::string &s)
{
    char buffer[65536];

    int txtlen=GetWindowTextLength(hwnd) + 1;
    GetWindowText(hwnd, buffer, txtlen);

    s = buffer;
    return txtlen;
}

HHOOK hhookCBTProc = 0;

LRESULT CALLBACK pfnCBTMsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam)
{
  if (nCode == HCBT_CREATEWND)
  {
    CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;

    if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
    {
      HWND hwnd = (HWND)wParam;

      // At this point you have the hwnd of the newly created
      // message box that so you can position it at will
      HDC test=GetDC(hwnd);
      //these 2 messages aren't showed
      if(SetTextAlign(test,TA_CENTER)==GDI_ERROR)
        MessageBox(NULL,"aligment", "error", MB_OK);
      if(SetWindowPos(hwnd, 0, 10,10,0,0,SWP_NOSIZE | SWP_NOZORDER)==FALSE)
        MessageBox(NULL,"position", "error", MB_OK);
      ReleaseDC(hwnd,test);
    }
  }

  return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}

void MessageBox(string text, string title="",UINT flags=MB_OK, bool modal=false)
{
    HWND parent=NULL;
    if(modal==true)
        parent=ActivatedForm;
    if(title=="")
    {
        GetWindowString(ActivatedForm,title);
    }
    if(hhookCBTProc==0)
        hhookCBTProc = SetWindowsHookEx(WH_CBT,
                                pfnCBTMsgBoxHook,
                                0, GetCurrentThreadId());
    if(hhookCBTProc==NULL)
        ::MessageBox(parent,"error","error", MB_OK);
    ::MessageBox(parent,text.c_str(),title.c_str(), flags);
    if(hhookCBTProc!=0)
        UnhookWindowsHookEx(hhookCBTProc);

}

i have an error on pfnCBTMsgBoxHook() function. how i know? the aligment and position aren't changed. why?
and no error messageboxes are showed

[Cambalinho]

changing the pcs->x and pcs->y values, the messagebox is changed in real time:

LRESULT CALLBACK pfnCBTMsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam)
{
  if (nCode == HCBT_CREATEWND)
  {
    CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;

    if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
    {
      HWND hwnd = (HWND)wParam;

      // At this point you have the hwnd of the newly created
      // message box that so you can position it at will
      //SendMessage(hwnd, WM_SETA ,(WPARAM) font, TRUE)
      RECT parentrct;
      
      GetWindowRect(ActivatedForm,&parentrct);
      LONG x=parentrct.left+(parentrct.right-parentrct.left)/2 - pcs->cx/2;
      LONG y=parentrct.top+(parentrct.bottom-parentrct.top)/2 - pcs->cy/2;
      pcs->x=x;
      pcs->y=y;
    }
  }

  return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}

anotherthing: we can't call UnhookWindowsHookEx() after show the messagebox... only when it's not needed.

the SendMessage() have 1 message for change the text aligment or is just for HDC?

[VladimirF]

1. Your test is strange: you are trying to create a MessageBox form the hook set on creation of message boxes; looks like infinite recursion.
2. Because of #1 and multiple other reasons, NEVER use MessageBox() for debugging/tracing. Instead, call ::OutputDebugString().

[Cambalinho]

1. Your test is strange: you are trying to create a MessageBox form the hook set on creation of message boxes; looks like infinite recursion.
2. Because of #1 and multiple other reasons, NEVER use MessageBox() for debugging/tracing. Instead, call ::OutputDebugString().

1 - humm.... confused me that
2 - i'm using the codeBlocks. for now, i don't know see the OutputDebugString() messages.
i'm reading: http://wiki.codeblocks.org/index.php...h_Code::Blocks
but i only see the watches window nothing more

[VladimirF]

2 - i'm using the codeBlocks. for now, i don't know see the OutputDebugString() messages.
i'm reading: http://wiki.codeblocks.org/index.php...h_Code::Blocks
but i only see the watches window nothing more

Try DebugView at http://technet.microsoft.com/en-us/s.../bb896647.aspx

[Cambalinho]

Try DebugView at http://technet.microsoft.com/en-us/s.../bb896647.aspx

thanks for all
going back to the code. the messagebox 1 STATIC child control, wright?
so i can catch its HWND:

HWND hwnd = (HWND)wParam;

        // At this point you have the hwnd of the newly created
        // message box that so you can position it at will
        //SendMessage(hwnd, WM_SETA ,(WPARAM) font, TRUE)

        HWND hwnd2 = FindWindowEx(hwnd, NULL, TEXT("STATIC"), NULL);
        if (hwnd2!=NULL)
            SetWindowLong(hwnd2, GWL_STYLE, GetWindowLong(hwnd2, GWL_STYLE) | SS_CENTER);
        else
            MessageBox(NULL, to_string(GetLastError()).c_str(), "error", MB_OK);

but the hwnd2 recives NULL. what you can tell me?
(the GetLastError() is 0)

[VladimirF]

...but the hwnd2 recives NULL. what you can tell me?

I can say that the STATIC child control is not yet created. Are you calling that from your HCBT_CREATEWND? If yes - it is too early. Try HCBT_ACTIVATE.

[Cambalinho]

I can say that the STATIC child control is not yet created. Are you calling that from your HCBT_CREATEWND? If yes - it is too early. Try HCBT_ACTIVATE.

yes you have wright. thanks:

HHOOK hhookCBTProc = 0;

LRESULT CALLBACK pfnCBTMsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam)
{
    if(nCode==HCBT_ACTIVATE)//center the text on STATIC child control
    {
        HWND hwnd = (HWND)wParam;
        HWND hwnd2 = FindWindowEx(hwnd, NULL,"STATIC",NULL);
        if (hwnd2!=NULL)
        {

            SetWindowLong(hwnd2, GWL_STYLE, GetWindowLong(hwnd2, GWL_STYLE) | SS_CENTER);
            //MessageBox(NULL, to_string(GetLastError()).c_str(), "error", MB_OK);
        }
    }
    else if (nCode == HCBT_CREATEWND)//center the messagebox on it's parent
    {
        CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;

        if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
        {
            //HWND hwnd = (HWND)wParam;

            // At this point you have the hwnd of the newly created
            // message box that so you can position it at will
            //SendMessage(hwnd, WM_SETA ,(WPARAM) font, TRUE)
            RECT parentrct;
            GetWindowRect(ActivatedForm,&parentrct);
            LONG x=parentrct.left+(parentrct.right-parentrct.left)/2 - pcs->cx/2;
            LONG y=parentrct.top+(parentrct.bottom-parentrct.top)/2 - pcs->cy/2;
            pcs->x=x;
            pcs->y=y;
        }
    }

  return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}

void MessageBox(string text, string title="",UINT flags=MB_OK | MB_ICONERROR, bool modal=true)
{
    HWND parent=NULL;
    if(modal==true)
        parent=ActivatedForm;
    if(title=="")
    {
        GetWindowString(ActivatedForm,title);
    }
    if(hhookCBTProc==0)
        hhookCBTProc = SetWindowsHookEx(WH_CBT,
                                pfnCBTMsgBoxHook,
                                0, GetCurrentThreadId());
    if(hhookCBTProc==NULL)
        OutputDebugString("error");
    ::MessageBox(parent,text.c_str(),title.c_str(), flags);
}

now i'm thinking on anotherthing, that i don't know how: can i do 2 new flags for the messagebox() and how can i test if that flag is used?

[VladimirF]

can i do 2 new flags for the messagebox() and how can i test if that flag is used?

What flags are you asking about? Could you please explain?

[Cambalinho]

What flags are you asking about? Could you please explain?

the messagebox() have MB_RIGHT, MB_OK and others. imagine that i want do more 2 MB_CENTER and MB_PARENTCENTER. what values can i use?

[Cambalinho]

i must create enum values\flags, but if i don't know, correctly, the messagebox flags values, i can't add them. so i inclued my own enum:

HHOOK hhookCBTProc = 0;

//for flags we must do 2^X
enum MessageBoxExtendedFlags
{
    MB_EX_NONE=1,  //2^0 = 1
    MB_EX_MODAL=2, //2^1 = 2
    MB_EX_PARENTCENTER=4, //2^2 = 4
    MB_EX_TEXTCENTER=8 //2^3 = 8
};

UINT MGBEXTENDED=0;

LRESULT CALLBACK MsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam)
{
    if(nCode==HCBT_ACTIVATE)//center the text on STATIC child control
    {
        HWND hwnd = (HWND)wParam;
        HWND hwnd2 = FindWindowEx(hwnd, NULL,"STATIC",NULL);
        if (hwnd2!=NULL && (MGBEXTENDED & MB_EX_TEXTCENTER))
        {
            SetWindowLong(hwnd2, GWL_STYLE, GetWindowLong(hwnd2, GWL_STYLE) | SS_CENTER);
            //MessageBox(NULL, to_string(GetLastError()).c_str(), "error", MB_OK);
        }
    }
    else if (nCode == HCBT_CREATEWND)//center the messagebox on it's parent
    {
        CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;

        if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
        {
            HWND hwnd = (HWND)wParam;

            // At this point you have the hwnd of the newly created
            // message box that so you can position it at will
            //SendMessage(hwnd, WM_SETA ,(WPARAM) font, TRUE)
            if(MGBEXTENDED & MB_EX_PARENTCENTER)
            {
                RECT parentrct;
                GetWindowRect(ActivatedForm,&parentrct);
                LONG x=parentrct.left+(parentrct.right-parentrct.left)/2 - pcs->cx/2;
                LONG y=parentrct.top+(parentrct.bottom-parentrct.top)/2 - pcs->cy/2;
                pcs->x=x;
                pcs->y=y;
            }
        }
    }

  return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}

int MessageBox(string text, string title="",UINT flags=MB_OK, UINT ExtendedFlags=MB_EX_NONE)
{
    HWND parent=NULL;
    MGBEXTENDED=ExtendedFlags;
    if(ExtendedFlags & MB_EX_MODAL)
        parent=GetForegroundWindow();
    if(title=="")
    {
        GetWindowString(ActivatedForm,title);
    }
    if(hhookCBTProc==0)
        hhookCBTProc = SetWindowsHookEx(WH_CBT,
                                MsgBoxHook,
                                0, GetCurrentThreadId());
    if(hhookCBTProc==NULL)
        OutputDebugString("error");
    return ::MessageBox(parent,text.c_str(),title.c_str(), flags);
}

maybe with time i can include the checkbox
out-off-topic: i have 2 windows(not child), 1 above other. on back isn't enabled and on front is.
heres the 2 situations:
1 - i'm on 2nd window and i show 1 messagebox. then i close the messagebox. and then the window. why the window on back loses the focus and other window\program get the focus?
2 - i close the 2nd window. the window on back get the focus... normal.
can anyone explain to me these ZOrder problem?