C / C++ / MFC

Re: Menu Item not being enabled??

27-Nov-07 9:48

any code inside ASSERT?
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Kiran Satish27-Nov-07 10:38

Kiran Satish

27-Nov-07 10:38

I am not sure what's happening, but in release mode whenever I run it from MS Visual C++ interface that menu item doesnt work as it should be, but when I run the application directly from release folder of the project it runs fine.

PKNT

Re: Menu Item not being enabled??

Kiran Satish28-Nov-07 5:04

Kiran Satish

28-Nov-07 5:04

How can I change the state of toolbar buttons at runtime. I tried using OnUpdateUI methods and it seems not to do what it is supposed to do. Is there any other way to do this?? I would like to enable or disable some toolbar buttons based upon user selection from menu.

thanks,

PKNT

CRuntimeClass - basic question - class access??

Vaclav_27-Nov-07 6:25

Re: CRuntimeClass - basic question - class access??

27-Nov-07 6:25

I am over my head again with the implementation of this "class" / structure.
Could someone please explain to me why the following code does what it does?

CRuntimeClass *pView_Tab = pVisualObject_tab->m_pRuntimeClass;

This code shows "normal " CRuntimeClass members of class CMyTabView.

CMyTabView *pTab = (CMyTabView*) pVisualObject_tab->m_pRuntimeClass;
pTab->AddTab("TEST");

And this one has same pointer and show the CMyTabView class and lets me run the AddTab of CMyTabView.

I have a debug trace but cannot paste it here
until I figure out how to copy it from IDE!

I need to run the AddTab function and like to know why these two lines have same pointer with “different results”.
I don’t think my code is right since it needs a cast to make it work. I think it defeats the intent of access to “runtime class”.

Thanks for you help.

Cheers
Vaclav

Mark Salsbery27-Nov-07 6:51

Mark Salsbery

27-Nov-07 6:51

Vaclav_Sal wrote:
CMyTabView *pTab = (CMyTabView*) pVisualObject_tab->m_pRuntimeClass;
pTab->AddTab("TEST");

I'm not sure I like that cast. Where did you get that code from?

What is pVisualObject_tab?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: CRuntimeClass - basic question - class access??

Vaclav_27-Nov-07 7:36

Re: CRuntimeClass - basic question - class access??

27-Nov-07 7:36

I don't like it either - the cast.
pVisualObject_tab is plain C++ class - not derived from anything!

(Maybe I should try to derive it from CObject - any thoughts on that?)

And the m_pRuntimeClass is CRuntimeClass *m_pRuntimeClass member of it.

I am really confused with this class / structure - it points to what?
It is "defined" as RUNTIME_CLASS(CMyTabView) but it does not let me access the class functions.
Thanks for your help Mark.

Mark Salsbery27-Nov-07 7:42

Mark Salsbery

27-Nov-07 7:42

Hmm, well you can cast pointers to other types but that doesn't change what the
pointer really points to. Just because the compiler lets you do it doesn't make it right.

The fact that you needed a cast should always be a warning sign.

Maybe back up a bit - what are you wanting or trying to do?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: CRuntimeClass - basic question - class access??

Vaclav_27-Nov-07 7:55

Re: CRuntimeClass - basic question - class access??

27-Nov-07 7:55

My basic problem is to understand how to access the runtime class using the CRuntimeClass structure.

I'll go back to books for now.
Thanks Vaclav

led mike27-Nov-07 8:01

led mike

27-Nov-07 8:01

Vaclav_Sal wrote:
My basic problem is to understand how to access the runtime class

I'm not convinced. I think your basic problem is you don't know "why" you think you need to access the runtime class. I think you are assuming you need to access the runtime class. You may be right, you may be wrong, I don't know.

Re: CRuntimeClass - basic question - class access??

Mark Salsbery27-Nov-07 8:04

Mark Salsbery

27-Nov-07 8:04

Here's a good place to start: CRuntimeClass Structure[^]

Maybe led mike linked to that as well - I'm too lazy to click his links Smile | :)

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: CRuntimeClass - basic question - class access??

led mike27-Nov-07 7:34

led mike

27-Nov-07 7:34

My initial reaction to your post is WTF?

You don't appear to have a proper understanding of CRuntimeClass.

Also....

Vaclav_Sal wrote:
This code shows "normal " CRuntimeClass members of class CMyTabView.

What does "This code shows" mean?

Vaclav_Sal wrote:
And this one has same pointer and show the CMyTabView class

again with the "show". Are you talking about viewing the pointer in the debugger? If so you don't appear to understand what "casting" is and how the debugger "watch" feature works. If you tell it a "foo" is a "bar" then it's going to show you the structure of a "bar" object in memory because that's what you told it to do when you "cast" it. It doesn't mean that the pointer actually points to a "bar" structure in memory.

Seems to me you need to do study casting a while longer until you understand it more completely. Perhaps you could start here[^].

Re: CRuntimeClass - basic question - class access??

Vaclav_27-Nov-07 7:49

27-Nov-07 7:49

Well my initial reaction was - thanks for nothing!
Would I ask these questions if I fully understood the subject of CRuntimeClass?
I do appreciate the link, thanks.
Vaclav

Offtopic

Nelek27-Nov-07 21:55

27-Nov-07 21:55

They maybe are sometimes a bit rude, but usually the "nothing" answers have helpfull information too. Just need to re read and analize without "offended feeling" (at least that's what I try when I get a "rude" answer)

Greetings.

--------
M.D.V. Wink | ;)

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson

Re: Offtopic

Vaclav_28-Nov-07 6:43

28-Nov-07 6:43

Nelek, your comments are appreciated.
I am well aware that everybody is different.
I don't think Led Mike was rude. I am just not impressed by his "WTF" remark as his first reaction and than him restating the obvious that I did not know the subject well. His link was constructive suggestion and appreciated.
PS The “mystery” of utilizing RUNTIME_CLASS macro is almost solved thanks to everybody input.

Cheers
Vaclav

VScroll - speed up

josip cagalj27-Nov-07 3:54

josip cagalj

27-Nov-07 3:54

Hi,
I'm reposting my problem with vertical scroling since no one is replaying eany more on my first thread.
So what I want is wnen I use mouse wheel to get scrolling faster, so upon sugetion from Nelek I'm doing this:

<br />
BOOL CMyView::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt)<br />
{<br />
int pos =GetScrollPos( SB_VERT );<br />
if (zDelta>0)<br />
OnVScroll(3*SB_LINEUP,pos,NULL);<br />
else if (zDelta<0)<br />
OnVScroll(3*SB_LINEDOWN,pos,NULL);<br />
return TRUE;<br />
}<br />

When I scroll by LINEDOWN it's OK, but when I do the oposite (SB_LINEUP) it has no effect, scrolling it slow again.
Why?
Thanks!

Re: VScroll - speed up

Nelek27-Nov-07 4:04

27-Nov-07 4:04

I don't know why, but have you tried with -3 * SB_LINEDOWN ??

Have you checked if SB_LINEDOWN == - SB_LINEUP ?

Mappng mode, one direction must be the different sign of the other

Greetings.

--------
M.D.V. Wink | ;)

What are you doing, man?

CPallini27-Nov-07 4:17

27-Nov-07 4:17

What are you doing, man?

josip cagalj wrote:
if (zDelta>0)
OnVScroll(3*SB_LINEUP,pos,NULL);
else if (zDelta<0)
OnVScroll(3*SB_LINEDOWN,pos,NULL);

Since (see winuser.h)

...
#define SB_LINEUP           0
#define SB_LINELEFT         0
#define SB_LINEDOWN         1
#define SB_LINERIGHT        1
#define SB_PAGEUP           2
#define SB_PAGELEFT         2
#define SB_PAGEDOWN         3
...

3*SB_LINEUP evaluates to SB_LINEUP itself.
while
SB_LINEDOWN evaluates to SB_PAGEDOWN.

Moving the wheel, you scroll a line up, a page down.

Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Nelek27-Nov-07 21:48

27-Nov-07 21:48

He wants to increase the speed on scrolling.

BTW, I thought the working area is 10 pages and 100 lines.

Quote from VC++ help:
You specify the amounts to scroll horizontally and vertically in logical units. By default, if the user clicks a scroll bar shaft outside of the scroll box, CScrollView scrolls a “page.” If the user clicks a scroll arrow at either end of a scroll bar, CScrollView scrolls a “line.” By default, a page is 1/10 of the total size of the view; a line is 1/10 of the page size. Override these default values by passing custom sizes in the SetScrollSizes member function. For example, you might set the horizontal size to some fraction of the width of the total size and the vertical size to the height of a line in the current font.

And winuser.h it says that page = 3*line...

Can you explain a bit more about? Because I am the one who told him to use the X*SB_PAGEUP/DOWN the other day. And now is a bit conusing for me too.

Greetings.

--------
M.D.V. Wink | ;)

CPallini27-Nov-07 22:09

27-Nov-07 22:09

Nelek wrote:
Override these default values by passing custom sizes in the SetScrollSizes member function

I think the above is the right approach.

On the other hand, the OP is hacking the nSBCode argument (of the method OnVScroll) that is just (MSDN):
a scroll-bar code that indicates the user's scrolling request.
i.e. a qualitative parameter rather than a quantitative one (like the amount of requested scroll).

Hope that helps
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Nelek27-Nov-07 22:27

27-Nov-07 22:27

CPallini wrote:
Nelek wrote:
Override these default values by passing custom sizes in the SetScrollSizes member function

I think the above is the right approach.

It depends on many things. I used this quantitative solution insteads of overriding the SetScrollSizes because my boss wanted UP/DOWN keys to scroll accuratelly and the wheel to do it faster but not changing a page that must stay as it was with PageUp/Down.

I ~~finally used that N*SB_LINEUP/DOWN~~ actually I used +-N*SB_LINEDOWN for the wheel to make it 3 times faster than keys or bar-arrow-clicks as he wanted.

And, as it worked fine for me (work right doesn't mean to be right, I know), I gave that option to him as well. Is there any way to do it just with "qualitative" parameter? Because I found no "fourth" messure to scroll a view. Just these 3: sizeTotal, sizePage, sizeLine...

VC++ 6.0

How can I solve that issue in a correct way?

Greetings.

--------
M.D.V. Wink | ;)

CPallini27-Nov-07 23:44

27-Nov-07 23:44

Nelek wrote:
+-N*SB_LINEDOWN

-N*SB_LINEDOWN (with N>0) should be meaningless to standard OnVScroll.

Even overriding OnVScroll to re-intepreter its first parameter doesn't seem to me a good design choice.

Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Nelek28-Nov-07 1:44

28-Nov-07 1:44

Aham,

then... how should I make to have a 3-speed scrolling as I explained but in a good structure? Line with arrow keys, middle with Wheel and Page with pageup/down keys or out the little bar at the scrollbar.

Greetings.

--------
M.D.V. Wink | ;)

CPallini28-Nov-07 2:24

Re: What are you doing, man? (secondary question solved)

28-Nov-07 2:24

Well a quite rude, but simple solution maybe issuing three times the call to OnVScroll (PostMessage ?) with either SB_LINEDOWN or SB_LINEUP.
Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Nelek28-Nov-07 3:05