C / C++ / MFC

12-Sep-02 7:29

CWnd::wndTop is MFC wrapper for HWND_TOP constant. Since you can't use constant where CWnd* is required, they had to create static object representing HWND_TOP value.

Tomasz Sowinski -- http://www.shooltz.com

To some its a six-pack, to me it's a support group

Re: What's wndTop?

introcosmo25-Jan-12 1:34

introcosmo

25-Jan-12 1:34

From CWnd

CListCtrl question

RK_200012-Sep-02 6:59

RK_2000

12-Sep-02 6:59

I have created a custom, called CCustomListCtrl that inherits from CListCtrl. The only reason for this was to use the CustomDraw features.

I am using this CCustomCtrl in a dialog box and I have created it dynamically as following:

DWORD dwStyle;
dwStyle = LVS_REPORT | WS_VISIBLE | WS_CHILD | WS_HSCROLL | WS_VSCROLL | WS_BORDER | LVS_SINGLESEL ;

m_ControllerList.Create(dwStyle,
CRect(nLeft, nTop, nRight, nBottom), this, IDC_CONTROLLER_LIST);

m_ControllerList.SetExtendedStyle(LVS_EX_CHECKBOXES | LVS_EX_FULLROWSELECT | LVS_EX_INFOTIP);

Now, I don't have trouble catching any of the messages pertaining to the list within the CDialog class but it seems like messages pertaining to the header of the list (i.e. ColumnClick, etc) are all going to the CCustomCtrl file and I just don't seem to be able to trap them in my dialog class.

any ideas?

Re: CListCtrl question

Tomasz Sowinski12-Sep-02 7:37

12-Sep-02 7:37

List control header's ID is zero. If you add handlers with ClassWizard, the message map entry will have control ID of your list, not zero. You'll have to change the ID value in message map or override OnNotify.

RK_2000 wrote:
I have created a custom, called CCustomListCtrl that inherits from CListCtrl. The only reason for this was to use the CustomDraw features.

You can use custom draw without creating new CListCtrl-based class. Message reflection makes it possible - handler will be created in dialog class and invoked whenever list needs painting.

Tomasz Sowinski -- http://www.shooltz.com

To some its a six-pack, to me it's a support group

Re: CListCtrl question

Michael Dunn12-Sep-02 18:21

Michael Dunn

12-Sep-02 18:21

RK_2000 wrote:
it seems like messages pertaining to the header of the list (i.e. ColumnClick, etc) are all going to the CCustomCtrl file

That's how WM_NOTIFY works. A notification sent by a control (in this case, the header) goes to the control's parent (the list).

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

MS Word in a Container

Anonymous12-Sep-02 6:58

Anonymous

12-Sep-02 6:58

I am currently trying to work with COM and make a container to hold a Word document. What is happening is that I create the frame window, then insert the Word document, and it does what it should, it brings up the doc, puts the Word toolbars and menus on the window, etc. But one thing it does that is strange is that it has several of the toolbar buttons disabled. The Open, New, and Save buttons are disabled. Also, the Print button is enabled but when I click on it, it doesn't do anything. Other buttons, such as the spell check work fine. Everything seems to work fine when using the menus. Does anyone know why these buttons are disabled? How to enable these buttons? Anything about this issue?

I looked through several articles, such as the Using MS Office in an MFC Application but that doesn't ever mention anything like this....

Buttons in a CListCtrl

MightyThor12-Sep-02 6:51

MightyThor

12-Sep-02 6:51

Hi,

How can i place buttons in a list control? Do i need declare the CListCtrl's and buttons' styles as owner drawn?
Do i need to override OnDrawItem function of CListCtrl because it takes DRAWITEMSTRUCT parameter which has a CtlType member that can take an ODT_BUTTON value. If not, how should i do that?

Help me out on this one please.

Thanks in advance.

Tomasz Sowinski12-Sep-02 7:44

12-Sep-02 7:44

Going owner-draw and setting CtlType won't take you anywhere; CtlType is set by Windows.

Do you want to create a column of buttons in your list control?

Tomasz Sowinski -- http://www.shooltz.com

To some its a six-pack, to me it's a support group

MightyThor12-Sep-02 8:19

MightyThor

12-Sep-02 8:19

Yes, i want one column of the control to have buttons. Actually, my aim is to make the user insert rows and the button will be created at runtime. But i don't know how to create unique IDs at runtime and how to handle messages for the new buttons. This is a further step but if you have any suggestions on this problem too, i would love to hear it.

For placing button in list, i found a way like below:

Adding the following code in OnPaint or OnCreate function does it:

CRect itemRect;
GetSubItemRect( 0, 0, LVIR_LABEL, itemRect );

CTeamButton *buttonx = new CTeamButton;
buttonx->Create( "Test", WS_CHILD|WS_VISIBLE, itemRect, this, 12345 );

But it doesn't seem to be a solid and gentle way. For example, when you resize the columns the buttons' size doesn't change. It would get worse when sorting takes place. So i can't count on it. Is there any subtle way to achieve this?

Thanks.

Tomasz Sowinski12-Sep-02 8:24

12-Sep-02 8:24

MightyThor wrote:
Is there any subtle way to achieve this?

I'm afraid not. You may consider switching to grid control instead, especially if you plan to add editing capabilities.

http://www.codeproject.com/miscctrl/gridctrl.asp[^]

If you want to stay with CListCtrl, I think it's better to give up 'real' buttons and simulate them with custom-draw or owner-draw.

Tomasz Sowinski -- http://www.shooltz.com

To some its a six-pack, to me it's a support group

finally dealing with 'new'

MightyThor12-Sep-02 9:06

MightyThor

12-Sep-02 9:06

I already checked grid control and it's a magnificent work, but the reason i'm trying to build my own component is mainly for self-education, so i better keep digging this custom-draw thing.

Thanks for your interest.

mini window

Zizilamoroso12-Sep-02 6:25

Zizilamoroso

12-Sep-02 6:25

What's the minimal windowstyle to be used with CreateWindow()?

If I use WS_POPUP, the window doesn't show up.

[VISUAL STUDIO 6.0] [MFC] [WIN98/2]

Re: mini window

Zizilamoroso12-Sep-02 6:27

Zizilamoroso

12-Sep-02 6:27

never mind, i forgot the width and height Blush | :O

[VISUAL STUDIO 6.0] [MFC] [WIN98/2]

ns12-Sep-02 6:19

12-Sep-02 6:19

Okay. I n many places I have stuff like:

m_FieldHolder = new CString [m_numFields ];

if the m_FieldHolder comes back as null, I will surely crash. This is in a function of a class, lets say. SO I of course can say:

if( m_FieldHolder)
{...
}

but what if its coming back as NULL? I will surely crash if I skip the code its supposed to do when not NULL. SO at this point, from the function in my class, how do I handle things? It would be nice to call a common global function each time new failed, but then do I exit? If I dont I cant predict what would happen since I have a zillion new, but in no case have I dealt with if its NULL then do what? I suppose I could pass info into my global NewFAilure() that would tell it which new it was that failed.

Ideas?
Thanks,
ns

C^hris L^osinger12-Sep-02 6:24

C^hris L^osinger

12-Sep-02 6:24

ns wrote:
Ideas?

check everywhere. return error codes from all your functions, test the error codes and react accordingly. alternately, you can use C++ exception handing (thorw, try, catch). but, either way, you have to test and you have to handle error conditions.

IMO, programming is 25% implementing the task at hand and 75% watching for things that can go wrong. nothing infuriates a user more than unexpected failures. imagine if IE crased every time it found a JPG it didn't like (bad example, it already does that)

-c

Greenspun's Tenth Rule of Programming:
"Any sufficiently complicated C or Fortran program contains an ad-hoc, informally-specified bug-ridden slow implementation of half of Common Lisp."

Le centriste12-Sep-02 7:43

Le centriste

12-Sep-02 7:43

_set_new_handler

Michel

It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a very long time to say, and to listen to.

- TreeBeard

Ravi Bhavnani12-Sep-02 10:32

Ravi Bhavnani

12-Sep-02 10:32

I agree with Chris' comment. Your code needs to test each point of failure and react accordingly. Basically, when a function fails, it returns with a failure code to the calling function, ad infinitum, until the top level caller is reached.

I'd just like to reiterate that you shouldn't be doing stuff like

if (m_FieldHolder) {
   ...
}

Instead, do

if (m_FieldHolder != NULL) {
   ...
}

Just my 2c worth!

/ravi

Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com

Michael Dunn12-Sep-02 18:29

Michael Dunn

12-Sep-02 18:29

ns wrote:
if( m_FieldHolder)

Actually, that's incorrect. MFC overrides operator new and if it fails, it throws a CMemoryException. So you need to wrap your allocations in try/catch blocks and handle that exception.

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

ns17-Sep-02 3:19

17-Sep-02 3:19

So if I already have a try-catch for COM errors in my code and I do a new in the try, I should add another catch?

Like
catch(CMemoryException *e)
{
}

Is the e coming in from the system?

Thanks,
ns