Thread: win32 - how can i put a child control always on top?

how can i put a child control always on top?
i did tryied with SetWindowPos() with HWND_TOPMOST. but i continue losing the Z-Order
is there any message that tell me when the Z-Order was changed?

Did you try using the HWND_TOP value instead of HWND_TOPMOST? I use HWND_TOP and it seems to work fine.

Also there is a window message - WM_WINDOWPOSCHANGED, which I believe is sent whenever the Z order changes.

You can also examine the window at the top and the next in order with GetTopWindow and GetNextWindow.

-

Originally Posted by megafiddle

Did you try using the HWND_TOP value instead of HWND_TOPMOST? I use HWND_TOP and it seems to work fine.

Also there is a window message - WM_WINDOWPOSCHANGED, which I believe is sent whenever the Z order changes.

You can also examine the window at the top and the next in order with GetTopWindow and GetNextWindow.

-

like you see i'm doing that:

Code:

//tooltip class:
const char tooltippropname[] = "propertytooltip";
const char tooltipclassprop[] = "classtooltip";

class tooltip
{
private:
    HWND hwnd=NULL;
    string strCaption="";
    boolean blnvisible=false;

    static LRESULT CALLBACK WndProcToolTip(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
    {
        WNDPROC oldproc = (WNDPROC)GetProp(GetParent(hwnd), tooltippropname);
        if (oldproc == NULL)
            MessageBox(NULL, "Can't find old procedure", "error", MB_OK | MB_ICONEXCLAMATION);

        //add the instance class to inst pointer
        tooltip *inst = (tooltip*)GetProp(hwnd, tooltipclassprop);
        if (inst == NULL || msg == WM_NCCREATE)
        {
            inst = (tooltip*)(((LPCREATESTRUCT)lParam)->lpCreateParams);
            SetProp(hwnd, tooltipclassprop, (HANDLE)inst);

        }
        if (inst == NULL)
            MessageBox(NULL, "Can't find the instance pointer", "error", MB_OK);

        switch(msg)
        {
            case WM_WINDOWPOSCHANGED:
            {
                if(IsWindowVisible(inst->hwnd)==true)
                {
                    SetWindowPos(inst->hwnd, HWND_TOP, 0, 0, 0, 0, SWP_SHOWWINDOW|SWP_NOSIZE|SWP_NOMOVE);
                    SetFocus(inst->hwnd);
                }

            }
            break;

            case WM_ERASEBKGND:
            {
                return TRUE;
            }
            break;

            case WM_PAINT:
            {
                PAINTSTRUCT  ps;
                BeginPaint(inst->hwnd, &ps);
                HTHEME hTheme = OpenThemeData(inst->hwnd, L"TOOLTIP");
                image imgtooltip(ps.rcPaint.right-ps.rcPaint.left,ps.rcPaint.bottom-ps.rcPaint.top);
                DrawThemeBackground(hTheme,imgtooltip,    TTP_STANDARD , TTSS_NORMAL,&ps.rcPaint, &ps.rcPaint);
                RECT a=ps.rcPaint;
                a.left=a.left+3;
                DrawThemeText(hTheme, imgtooltip, TTP_STANDARD , TTSS_NORMAL, towstring(inst->strCaption).c_str(),-1,DT_LEFT|DT_HIDEPREFIX,0,&a);
                CloseThemeData(hTheme);
                region n(imgtooltip, GetPixel(imgtooltip,0,0));
                SetWindowRgn(inst->hwnd,NULL,TRUE);
                SetWindowRgn(inst->hwnd,n,TRUE);
                //BitBlt(ps.hdc,0,0,ps.rcPaint.right-ps.rcPaint.left,ps.rcPaint.bottom-ps.rcPaint.top,imgtooltip,0,0,SRCCOPY);
                TransparentBlt(ps.hdc,0,0,ps.rcPaint.right-ps.rcPaint.left,ps.rcPaint.bottom-ps.rcPaint.top,imgtooltip,0,0,ps.rcPaint.right-ps.rcPaint.left,ps.rcPaint.bottom-ps.rcPaint.top, GetPixel(imgtooltip,0,0));
                EndPaint(inst->hwnd, &ps);
            }
            break;

            case WM_RBUTTONUP:
            {
                ShowWindow(inst->hwnd, FALSE);
                RECT b;
                GetWindowRect(GetParent(inst->hwnd),&b);
                InvalidateRect(GetParent(inst->hwnd),&b,TRUE);
            }
            break;
        }
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }

    void setParent(HWND parent=WindowMain)
    {
        if (hwnd==NULL)
        {
            WNDCLASS tooltipclass;
            HINSTANCE mod = (HINSTANCE)GetModuleHandle(NULL);

            ZeroMemory(&tooltipclass, sizeof(WNDCLASS));
            GetClassInfo(mod, TEXT("BUTTON"), &tooltipclass);

            tooltipclass.hInstance = mod;
            tooltipclass.lpszClassName = TEXT("tooltip");
            tooltipclass.style=CS_DBLCLKS | CS_DROPSHADOW;


            // store the old WNDPROC of the button window class
            SetProp(parent, tooltippropname, (HANDLE)tooltipclass.lpfnWndProc);
            // replace it with local WNDPROC

            tooltipclass.lpfnWndProc = WndProcToolTip;
            tooltipclass.hbrBackground = (HBRUSH) GetStockBrush(NULL_BRUSH);

            // register the new window class"
            RegisterClass(&tooltipclass);

            hwnd = CreateWindowEx(
                WS_EX_TOPMOST,
                TEXT("tooltip"),//these must be the same of  ButtonClass.lpszClassName.. registed class
                strCaption.c_str(),
                BS_OWNERDRAW |WS_TABSTOP| BS_NOTIFY | WS_CHILD, //onerdraw for add images
                CW_USEDEFAULT, CW_USEDEFAULT, 100, 100,
                parent,
                0,
                mod,
                this);

            if (hwnd == NULL)
                MessageBox(NULL, "Can't create the control", "error", MB_OK);

            if (SetProp(hwnd, tooltipclassprop, (HANDLE)this) == 0)
                MessageBox(NULL, "can't set the class property", "error", MB_OK);
            RECT textrect={0};
            HDC txthdc=GetDC(hwnd);
            DrawText (txthdc,strCaption.c_str(),-1,&textrect,DT_CALCRECT);
            SetWindowPos(hwnd, HWND_TOP, 0, 0, textrect.right-textrect.left, textrect.bottom, SWP_NOMOVE | SWP_FRAMECHANGED | SWP_HIDEWINDOW);
            RECT d;
            GetClientRect(hwnd,&d);
            InvalidateRect(hwnd,&d,TRUE);
        }
        else
        {
            SetParent(hwnd,parent);
        }
    }

public:
    ~tooltip()
    {
        DestroyWindow(hwnd);
    }

    tooltip(string text="")
    {
        strCaption=text;
        setParent();
        if(hwnd==NULL)
            MessageBox(NULL,"error","error", MB_OK);
    }

    property<boolean> visible
    {
        Get(boolean)
        {
            return blnvisible;
        },
        Set(boolean blnVisible)
        {
            blnvisible=blnVisible;
            if (blnvisible==true)
            {
                ShowWindow(hwnd,TRUE);
                RECT d;
                GetClientRect(hwnd,&d);
                InvalidateRect(hwnd,&d,TRUE);
            }
            else
            {
                ShowWindow(hwnd,FALSE);
                RECT b;
                GetWindowRect(GetParent(hwnd),&b);
                InvalidateRect(GetParent(hwnd),&b,TRUE);
            }
        }

    };

    void show(int posx, int posy)
    {
        blnvisible=true;
        RECT textrect={0};
        HDC txthdc=GetDC(hwnd);
        DrawText (txthdc,strCaption.c_str(),-1,&textrect,DT_CALCRECT);
        SetWindowPos(hwnd, HWND_TOP, posx, posy, textrect.right, textrect.bottom, SWP_NOMOVE | SWP_FRAMECHANGED);
        RECT d;
        GetClientRect(hwnd,&d);
        InvalidateRect(hwnd,&d,TRUE);
    }

    void show()
    {
        //Getting mouse cursor coordenates
        POINT a;
        GetCursorPos(&a);
        ScreenToClient(GetParent(hwnd),&a);


        //Getting mouse cursor size
        ICONINFO ii;
        GetIconInfo(GetCursor(), &ii);
        BITMAP bm;
        GetObject( ii.hbmColor, sizeof( bm ), &bm );
        //bm.bmHeight = ii.hbmColor ? bm.bmHeight : bm.bmHeight / 2;
        //Show the ToolTip
        blnvisible=true;
        RECT textrect={0};
        HDC txthdc=GetDC(hwnd);
        DrawText (txthdc,strCaption.c_str(),-1,&textrect,DT_CALCRECT);
        SetWindowPos(hwnd, HWND_TOP, a.x , a.y + bm.bmHeight/2 + 3, textrect.right, textrect.bottom, SWP_SHOWWINDOW| SWP_FRAMECHANGED | SWP_DRAWFRAME);
        RECT d;
        GetClientRect(hwnd,&d);
        InvalidateRect(hwnd,&d,TRUE);
    }

    property<string> caption
    {
        Get(string)
        {
            return strCaption;
        },
        Set(string strtext)
        {
            strCaption=strtext;
            RECT textrect={0};
            HDC txthdc=GetDC(hwnd);
            DrawText (txthdc,strCaption.c_str(),-1,&textrect,DT_CALCRECT);
            SetWindowPos(hwnd, HWND_TOP, 0, 0, textrect.right-textrect.left, textrect.bottom, SWP_NOMOVE | SWP_FRAMECHANGED);
            RECT b;
            GetWindowRect(hwnd,&b);
            InvalidateRect(hwnd,&b,TRUE);
        }
    };
};

the 1st time, the control is showed on top. but when the back control is drawed(wM_PAINT), i lose the top most

Code:

case WM_WINDOWPOSCHANGED:
            {
                if(IsWindowVisible(inst->hwnd)==true)
                {
                    SetWindowPos(inst->hwnd, HWND_TOP, 0, 0, 0, 0, SWP_SHOWWINDOW|SWP_NOSIZE|SWP_NOMOVE);
                    SetFocus(inst->hwnd);
                }

            }
            break;

The IsWindowVisible function only tests to see if the WS_VISIBLE bit was set. If WS_VISIBLE wasn't specified, the if statement will never be true.

-

Originally Posted by megafiddle

Code:

case WM_WINDOWPOSCHANGED:
            {
                if(IsWindowVisible(inst->hwnd)==true)
                {
                    SetWindowPos(inst->hwnd, HWND_TOP, 0, 0, 0, 0, SWP_SHOWWINDOW|SWP_NOSIZE|SWP_NOMOVE);
                    SetFocus(inst->hwnd);
                }

            }
            break;

The IsWindowVisible function only tests to see if the WS_VISIBLE bit was set. If WS_VISIBLE wasn't specified, the if statement will never be true.

-

sorry but i only get lucky with these function:

Code:

void SetTopMost( HWND hWnd)
{
    if(IsWindowVisible(hWnd)==TRUE)
    {
        ShowWindow(hWnd,SW_HIDE);
        ShowWindow(hWnd,SW_SHOW);
    }
}

and called after paint it on WM_PAINT.
isn't a 100% because it can 'flicker' sometimes. but it's great

i resolved in diferent way :P
i add the WS_CLIPSIBLINGS flag, when i create the control. and now i can change the Z-Order without drawing problems.
(the WS_CLIPSIBLINGS flag is for child controls and the WS_CLIPCHILDREN flag is for parent control)