C / C++ / MFC Discussion Boards

Alvaro Mendez19-Nov-02 6:26

19-Nov-02 6:26

Funny how easily some people say they don't like something but yet don't offer an alternative. I would tell your boss that unless he knows of an alternative, that a 3-state checkbox is the way to go. It's a standard Windows behavior:

Checked on White = all of the options are selected
Checked on Gray = some options are selected, some aren't
Not Checked = none of the options are selected

I've seen this type of checkbox in installation programs more than anything else. How are you planning on using yours?

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Re: Tri - State button

Anonymous19-Nov-02 6:32

Anonymous

19-Nov-02 6:32

It will be used as a binary toggle, either it is 1, 0, or neither. He likes how it works he just thinks that when it is in the neither(gray) state it looks too much like the ones that are disabled. There are a few places where it will be mixed in with disabled options. Visually it is difficult to tell the difference until you click on it.

Amy

Re: Tri - State button

Alvaro Mendez19-Nov-02 6:48

Alvaro Mendez

19-Nov-02 6:48

The only alternative I can think of is radio buttons. They occupy more space but they should definitely clear things up on your dialog box:

Do you like this?    O Yes   O No   O Dunno

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Re: Tri - State button

Amy Patterson19-Nov-02 7:11

Amy Patterson

19-Nov-02 7:11

Thanks,
Do you know if it is possible to change the color of the regular tri-state checkbox?

Amy

How to get the difference between two variables of type DATE !!

bahruddina19-Nov-02 5:56

bahruddina

19-Nov-02 5:56

hi,

I need to get the difference (in minute) between two variables of type DATE.
Example:

<br />
DATE d1; //   12/12/2002 12:10:20 AM<br />
DATE d2; //   11/12/2002 11:10:20 AM

Thanks in advance
Newbie

Re: How to get the difference between two variables of type DATE !!

C^hris L^osinger19-Nov-02 6:02

C^hris L^osinger

19-Nov-02 6:02

see the COleDateTime and COleDateTimeSpan classes.

-c

A conclusion is simply the place where someone got tired of thinking.

Smaller Animals Software

Re: How to get the difference between two variables of type DATE !!

Alvaro Mendez19-Nov-02 6:10

Alvaro Mendez

19-Nov-02 6:10

The easiest way is to convert the DATEs to COleDateTime objects and use the COleDateTimeSpan class to determine the difference:

COleDateTime dtm1 = d1;
COleDateTime dtm2 = d2;
 
int minutes = static_cast<int>((dtm1 - dtm2).GetTotalMinutes());

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Drag And Droppings ...

Maximilien19-Nov-02 5:34

Maximilien

19-Nov-02 5:34

Howdy'

I'm trying to implement a simple drag'n'drop of objects and I want to be able to drop them outside my application to create new windows ( i.e. detach some element from the main window )

I'm now use the drag'n'drop mechanism to drag some info between the source and the target, which is ok, but I don't/can't drop to somewhere else ?

[Question part ... ]
I've added a derived COleDropTarget to my mainframe and registered the target window, all is working ok inside the application, but I don't exactly know what to register if I let go of the button anywhere else on the screen, whether it's the desktop window, or any other windows under the mouse at that point; I don't think that I have to register a type because I'm not using the clipboard.

The other alternative that I'm trying , is to "simulate" the drag'n'drop by capturing the mouse ( SetCapture ) and processing stuff in the MouseMove and on the MouseUp, do the "drop"; I'm loosing some of the functionnalities that the drag'n'drop automatically offer.

Thanks, and sorry for the rambling ...

Max.

Re: Drag And Droppings ...

Paul M Watt19-Nov-02 9:59

Paul M Watt

19-Nov-02 9:59

It seems to me that your simulation technique would be a good method, and I see your point about losing certain Drag and Drop functionality that OLE provides for you.

What if you were to create a transparent window, that fit over the entire desktop when these particular items were to be dragged off of your main window. Then your transparent window with no borders, no caption, and no paint routines could become a drop target. When the user cancelled the drag and drop, or after they dropped the item on your transparent window, the window would go away.

Good Luck

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Dumb question..

RobJones19-Nov-02 5:28

RobJones

19-Nov-02 5:28

Hello,
This is probably a really dumb question.. I created a SDI with a splitter.. when I close the app it asks me if I want to save before exit.. How do I get rid of that prompt? Over ride one of the OnClose functions?

Thanks,
Rob

Re: Dumb question..

C^hris L^osinger19-Nov-02 6:00

C^hris L^osinger

19-Nov-02 6:00

that's one way. another way would be to set the doc's modified flag to FALSE. (SetModifiedFlag(FALSE)). that should do it.

-c

A conclusion is simply the place where someone got tired of thinking.

Smaller Animals Software

Re: Dumb question..

Alvaro Mendez19-Nov-02 6:02

Alvaro Mendez

19-Nov-02 6:02

The problem has to do with the modified flag inside your document being set somehow. Read up on SetModifiedFlag, IsModified, and SaveModified.

It seems to me like the quickest solution is just to override SaveModified in your CDocument-derived class and make it return TRUE:

BOOL CYourDocument::SaveModified()
{
  return TRUE;
}

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Re: Dumb question..

RobJones19-Nov-02 6:09

RobJones

19-Nov-02 6:09

Works perfect, Thanks to both of you!

static_cast

Jon Hulatt19-Nov-02 5:14

Jon Hulatt

19-Nov-02 5:14

hi all,

I'm trying to do an strcmp() with a REG_SZ value.

I'm loading the REG_SZ into an unsigned char[] like this:-

unsigned char lpstrValueData[MAX_PATH];
dwRegStatus=RegQueryValueEx(hKey, "DisplayName", NULL, &dwType, static_cast<LPBYTE>(lpstrValueData), &dwcbData);

then, i want to compare it with a string...

strcmp(lpstrValueData, "MyString");

Perhaps obviously, this doesn't work becuase:-
error C2664: 'strcmp' : cannot convert parameter 1 from 'unsigned char [260]' to 'const char *'

so, i try this instead:-

strcmp( static_cast<const char *>(lpstrValueData), "MyString");

but this doesn't work either:-
error C2440: 'static_cast' : cannot convert from 'unsigned char [260]' to 'const char *'

which is wierding me out. A nasty C style cast like this works:-

strcmp( (const char *) lpstrValueData, "MyString");

so why doesn't static_cast like it?

The expression static_cast < type-id > ( expression ) converts expression to the type of type-id based solely on the types present in the expression. No run-time type check is made to ensure the safety of the conversion.

help!

#include <beer.h>

Re: static_cast

Joaquín M López Muñoz19-Nov-02 5:33

Joaquín M López Muñoz

19-Nov-02 5:33

If you don't like the C cast syntax, you can resort to reinterpret_cast (which is basically the same). I sort of agree with you that static_cast whould be allowed here, but alas C++ rules are the way they are.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Re: static_cast

Jon Hulatt19-Nov-02 5:52

Jon Hulatt

19-Nov-02 5:52

Thanks Joaquín!

#include <beer.h>

Re: static_cast

Tim Smith19-Nov-02 6:04

Tim Smith

19-Nov-02 6:04

Not too shocking since they are two totally different types.

Tim Smith

I'm going to patent thought. I have yet to see any prior art.

Re: static_cast

Paul M Watt19-Nov-02 10:05

Paul M Watt

19-Nov-02 10:05

static_cast is a compiler time casting operator that insures type safety. So nothing is done at runtime when you use the static_cast.

reinterpret_cast is more like the C-style cast. It basically says that you are going to take responsibility for the casting that is done, and there is no type-safety checking performed with this cast.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: static_cast

Patje19-Nov-02 21:17

Patje

19-Nov-02 21:17

Doesn't that depend on the type of casting performed?
E.g. Take the following C lines:

myInt     = (int)myFloat;<br />
myCharPtr = (char *)myVoidPtr;

I would use static_cast for the first one, and reinterpret_cast for the second one.

If I would use
myInt = reinterpret_cast<int>myFloat;wouldn't that cause the compiler to intepret the bit-pattern of myFloat as the bit-pattern of an int, causing garbage to be assigned to myInt?

That leaves me with the other two casts:
const_cast: for casting way the const (wouldn't volatile_cast be a better name?)
dynamic_cast: for casting instance-pointers from one type to another, checking dynamically whether it is the correct type or not.

<marquee>Enjoy life, this is not a rehearsal !!!

Crash in CReBar::AddBar() under .Net

pvlasie19-Nov-02 4:39

pvlasie

19-Nov-02 4:39

I have this weird problem where a call to CReBar::AddBar() crashes my
program.

This only happens in VC++ .Net in Release mode. If I run the code from the
debugger (F5) it doesn't happen. If I compile a debug version of the code it
doesn't happen either.

So basically I get a crash every time I compile a release build and I
execute the program from outside the debugger.

As you can imagine, I'm having a very hard time debugging this! Smile | :)

Has anyone seen this problem before? Any idea what might be causing this?
Any suggestion/idea is welcome. Thank you.

Where custom ie toolbar is located?

Weiye Chen19-Nov-02 4:17

Weiye Chen

19-Nov-02 4:17

Anyone knows where can i remove those custom ie toolbars installed by other programs?? Is it somewhere in the registry?

Weiye, Chen
When pursuing your dreams, don't forget to enjoy your life...

Re: Where custom ie toolbar is located?

Chris Hambleton19-Nov-02 11:54

Chris Hambleton

19-Nov-02 11:54

Search MSDN for the following (all as 1 string):

tutorial custom toolbar buttons internet explorer bar

then select the article titled "Adding toolbar buttons" in the internet explorer SDK - this will tell you how to add & remove toolbar buttons from IE...

"No one goes to hell because of their sin, but because of rejecting God's method of salvation: His Son's life for yours..."

"It does not take a majority to prevail ... but rather an irate, tireless minority, keen on setting brushfires of freedom in the minds of men." --Samuel Adams

Digital timer MFC/C++

Justina0119-Nov-02 3:39

Justina01

19-Nov-02 3:39

I'm trying to program a timer in MFC/C++ and I'm having trouble with my start-button. When I push the start-button it is supposed to call a function that reads the time (hour, minute, second) as a string and the start the countdown (which also should be seen on the screen) by seconds.
Is there someone who can give me an idea of how this would look like?
Thanks!;)

MFC beginner

Re: Digital timer MFC/C++

RobJones19-Nov-02 5:31

RobJones

19-Nov-02 5:31

I would start here.. http://www.codeproject.com/staticctrl/CClockST.asp[^]

Re: Digital timer MFC/C++

valikac19-Nov-02 7:26

valikac

19-Nov-02 7:26

One solution is to add a message handler for the button. Call the timer function inside that button handler.

Kuphryn

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