ATL / WTL / STL

Re: Subclassing a CScrollContainerImpl<> derived class

8-Sep-05 3:12

I did a CScrollContainerImpl<> derived class that works fine, if I use Create().

What I wan't to do now is subclass a control on a dialog, so I can set the initial size and position via the dialog editor.

Now my problem is, that if I use a Static label as my placeholder I can't get the scrollbars to work.

If I click them nothing happens, what did I do wrong.

I also tried to use a custom contol as a place holder, but i don't know how to register Controls Window class correctly.

This must be a common problem, and maybe some pro can tell me the correct solution to it?

-- modified at 4:55 Tuesday 13th September, 2005

Jochen Heckl11-Sep-05 22:57

Re: Subclassing a CScrollContainerImpl derived class

11-Sep-05 22:57

Come on somebody, please.
Some Pro to help me? Wink | ;-)

Igor Vigdorchik13-Sep-05 15:25

Igor Vigdorchik

13-Sep-05 15:25

Did you call SubclassWindow() in OnInitDialog() like so:

CMyWindow m_wnd;<br />
<br />
BOOL bRet = m_wnd.SubclassWindow(GetDlgItem(IDC_MY_CONTROL));<br />
ATLASSERT(bRet);

And why did you use a static control, probably you should use a scrollbar control.

Re: Subclassing a CScrollContainerImpl derived class

Jochen Heckl13-Sep-05 23:38

Re: Subclassing a CScrollContainerImpl derived class

13-Sep-05 23:38

Hi Igor, thank you for answering.

I got exactly this code in my project (but the Variable names).

But it does not work. Scrolling via the mouseweel works fine, but there is no reaction when clicking the up/down buttons of the scroll bar. Neither when I'm trying to drag the scroll bar marker up or down.

Can I use a scrollbar here, that is going to be subclassed? I need a entire control, that can have a vertical and a horizontal scrollbar. Showing or hiding the scrollbars im managed by CScrollContainerImpl<>.

My class declaration looks something like that:

<br />
class CtrlPanel : public CScrollContainerImpl< CtrlPanel ><br />
{<br />
public:<br />
	DECLARE_WND_CLASS( _T("CtrlPanel") )<br />
<br />
	BEGIN_MSG_MAP_EX( CtrlPanel )		<br />
		MSG_WM_ERASEBKGND( OnEraseBkgnd )<br />
		CHAIN_MSG_MAP( CScrollContainerImpl< CtrlPanel > )		END_MSG_MAP()<br />
<br />
public:<br />
	CtrlPanel( void );<br />
	virtual ~CtrlPanel( void );<br />
<br />
        // not used when subclassing<br />
	HWND Create( HWND i_hParent );<br />
	<br />
	// CScrollContainerImpl interface<br />
	void UpdateLayout( void );<br />
	void DoPaint( CDCHandle i_DCHandle ) {};<br />
<br />
private:<br />
	// message handlers<br />
	LRESULT OnEraseBkgnd( HDC i_hDC );<br />
};<br />

This class later creates controls that are placed on it.

in UpdateLayout() I compute the size and position of each control, than i set the scrollsize...:

<br />
// ...<br />
// ...<br />
// Position panel controls.<br />
// Compute ScrollsizeX and ScrollsizeY.<br />
// ...<br />
// ...<br />
<br />
SetScrollSize( std::max( 1, ScrollSizeX ), std::max( 1, ScrollSizeY ) );<br />

Still, what am I doing wrong Frown | :-(

Igor Vigdorchik14-Sep-05 7:11

Igor Vigdorchik

14-Sep-05 7:11

Just a thought - maybe you need to handle all events yourself. Check codeproject articles on this subject (even MFC), see how what approach is used there. Sorry, can't give you more help.

Good luck.

Re: WTL - Subclassing a CScrollContainerImpl derived class

Jochen Heckl19-Sep-05 0:22

ATL COM wrapper: Link Error

19-Sep-05 0:22

Here I got an other approach to the question.

"How do I correctly subclass a CScrollContainerImpl?"

I guess a huge amount of developers has done this, but I simply cant gat it to work right. Still the scrollbars of static refuse to work.

So, if you managed to it - tell me how, please Wink | ;-)

.

What contol do you put on your dialog to be subclassed?
Do you take care for any WMessgas, but those handled by CScrollContainerImpl<>?

rbrad123458-Sep-05 2:04

8-Sep-05 2:04

Hello everyone,

Im new to the world of ATL and COM and am trying to create a wrapper class for a eVC++ library. I had the library working fine in a simple MFC app I wrote but the Linker fails in an ATL COM project I've created. Following is the error I receive.

wrapper.obj : error LNK2019: unresolved external symbol __imp__Read referenced in function "public: virtual long __cdecl CReader::InitReader(void)" (?InitReader@CReader@@UAAJXZ)

I'm guessing this error is due to a mis-understanding (on my part) of how ATL and COM link in external libraries. I was able to force the same error message in my MFC app by removing the .lib in "Project->Settings->Link:Object/Library Modules" which tells me that the Linker isnt seeing the library for some reason.

Any help is much appreciated!!

Thanks,

Ryan Bradley

Jörgen Sigvardsson8-Sep-05 9:52

8-Sep-05 9:52

Did you __declspec(dllexport) your class from your DLL, and __declspec(dllimport) from the DLL client? Unsure | :~

Good music: In my rosary[^]

rbrad123459-Sep-05 3:21

9-Sep-05 3:21

The library was provided to me by a vendor. Using "dumpbin.exe /exports" I can see the calls I need to make. I'm using the same .H file to __declspec(dllimport) in my ATL/COM project as with the MFC project that works.

That is what is confusing me. I'd guessed there is something different about how an ATL/COM project would attempt to link. This has to be something elementary that Im just missing.

Ryan Bradley

rbrad123459-Sep-05 12:05

9-Sep-05 12:05

Now this is interesting...

The symbols the linker errors out on are slightly different between the ATL/COM and the MFC app. The ATL/COM object is looking for __imp__Read while the MFC app is looking for __imp_Read.

I can open up the .lib file in notepad and see __imp_Read. Any ideas?? Dead | X|

Ryan Bradley

-- modified at 18:07 Friday 9th September, 2005

Jörgen Sigvardsson9-Sep-05 12:15

9-Sep-05 12:15

Hmm.. I think I know what it could be. IIRC, __cdecl functions are always given an _ prefix, while __stdcall aren't. Try with __cdecl or __stdcall (I'm too tired to sort out which one you need right now.. Sleepy | :zzz:

)

Good music: In my rosary[^]

-- modified at 18:15 Friday 9th September, 2005

rbrad123459-Sep-05 14:20

9-Sep-05 14:20

Thanks for mentioning that. I think it is a piece of the puzzle. __cdecl decorates names while __stdcall does not. I've added #error directives to my header to ensure that __stdcall is used and it is. I've tried using __cdecl and it simply gives additional errors.

My header prototypes "__declspec(dllimport) int __stdcall Read()"
Despite all this sanity checking the linker is still looking for __imp__Read and not __imp_Read as it should.

Ryan Bradley

Jörgen Sigvardsson9-Sep-05 22:32

why can't I change the static text color?

9-Sep-05 22:32

Man, I'm suffering with you. Linking errors are not fun. Frown | :(

Good music: In my rosary[^]

Transparent combobox

Asha Udupa5-Sep-05 1:44

Asha Udupa

5-Sep-05 1:44

Hi
I have a WTL dialog box which is a layered window. I have used the following code
::SetWindowLong(m_hWnd, GWL_EXSTYLE, ::GetWindowLong(m_hWnd, GWL_EXSTYLE) | WS_EX_LAYERED);
g_pSetLayeredWindowAttributes(m_hWnd, 0, bAlpha, LWA_ALPHA);

where g_pSetLayeredWindowAttributes = (lpfnSetLayeredWindowAttributes)
GetProcAddress(hUser32, "SetLayeredWindowAttributes");

It works fine. I have another dialog dlg1, which I am going to display on some events in the main window.There is a combobox in the dlg1. when I click on combobox,portion of the combobox becomes transparent. It works fine with all other controls in dlg. Any idea?

Regards

lvjing794-Sep-05 21:02

lvjing79

4-Sep-05 21:02

I create an activex control(composite control) with ATL. Now I want to change the static's text color in the dialogbox.I do it like this:

HDC hdc = ::GetDC(GetDlgItem(IDC_STATIC_STATUS));
SetTextColor(hdc, 0x000000ff);

These two sentences are in the OnInitDialog function, but after this the color don't change.
Who can tell me why? And what shoud I do to change the color?Thanks.

Jörgen Sigvardsson5-Sep-05 6:52

5-Sep-05 6:52

You need to handle the WM_CTLCOLORSTATIC message in the dialog. That message will give you the HDC being used to draw the static control. Just set the text color on that DC, and you will achieve what you want.

For more info, see the MSDN docs.

Good music: In my rosary[^]

lvjing795-Sep-05 16:42

lvjing79

5-Sep-05 16:42

Jörgen Sigvardsson,thanks very much, I have successfully set the text color and I found that I should put MESSAGE_HANDLER(WM_CTLCOLORSTATIC, OnCtlColorStatic) before CHAIN_MSG_MAP, if not, it didn't work Smile | :)

lvjing796-Sep-05 0:19

lvjing79

6-Sep-05 0:19

Another question, there is a sentence in the MSDN:
"The system does not automatically destroy the returned brush. It is the application's responsibility to destroy the brush when it is no longer needed.
"
I wonder when I should destroy the brush and where did I get the brush's handle?

-- modified at 6:22 Tuesday 6th September, 2005