C / C++ / MFC

12-Feb-02 17:58

Is it bad programming practice to use properties in your ATL components.

I mean which of the two is better :-

(1) Function(arg1, arg2, arg3)

(2)
arg1=100
arg2=100
arg3=200
Function()

The reason why I'd like to use properties is that I am planning to write some components for use from ASP. And the normal ASP/VB way is to use properties, I think so anyway.

Any ideas or suggestions on this are appreciated.

Thanks in advance.

Nish [ATL newbie]

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Derek Waters12-Feb-02 18:40

Derek Waters

12-Feb-02 18:40

I would say (and, to state again, this is only MY opinion)...

Only use a property if:
a) It is going to be persistent (stored with the object) or
b) It is used in more than one method in the object.

Use parameters if the values are only going to be used in that method, otherwise you're incurring the penalty of making COM calls for each parameter and then the method as well.

So, I think you can read that as suggesting parameters.

Also, in ASP you can quite happily use parameters, just like a Sub.

MyObject.MyMethod "Parameter 1", viParameter2, "Some Other Parameter"

------------------------
Derek Waters
derek@lj-oz.com

Nish Nishant12-Feb-02 22:44

12-Feb-02 22:44

Derek Waters wrote:
Use parameters if the values are only going to be used in that method, otherwise you're incurring the penalty of making COM calls for each parameter and then the method as well

Thanks a lot Derek. That was very useful.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

Ravish12-Feb-02 19:00

Ravish

12-Feb-02 19:00

With properties your component acquires state, so maynot scale well when deployed in MTS where Just in Time activation and ASAP deactivation help in improving throughput. Also if the components are deployed in remote machine or as out of proc components, look at the extra marshalling, network calls.

Nish Nishant12-Feb-02 22:45

12-Feb-02 22:45

Thanks Ravish.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

13-Feb-02 6:39

It is fine if you plan to use stateful programs.

If eventually, your app and the number of components grow

Using properties vs just methods or functions with parameters will slow down the application.

Using properties
1) More Overhead is created marshalling the asp - com calls
2) Limited threads in IIS are consumed longer by stateful components
3) There is an increase in RPC calls if dcom is used

Do you think you could solve my problem?
http://www.codeproject.com/script/comments/forums.asp?forumid=1647&select=114120&tid=114120#xx114120xx

Safearray and COM+

Nish Nishant13-Feb-02 16:37

How can i change application icon

13-Feb-02 16:37

Thank you.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

12-Feb-02 14:34

How can i change application icon dinamicaly?

moliate12-Feb-02 14:42

moliate

12-Feb-02 14:42

If using MFC: CWnd::SetIcon

/moliate

12-Feb-02 15:13

Icon must be stay changed after close application (In Explorer - another icon).

Nish Nishant12-Feb-02 16:28

12-Feb-02 16:28

You cant change your exe file's icon dynamically. You'd have to recompile it with a new icon. Unless you figure out some way to open the file and overwrite the icon with a new one.

Nish

Nish was here, now Nish has gone;
He left his soul, to turn you on;
Those who knew Nish, knew him well;
Those who didn't, can go to hell.

I like to Jig | [Dance]

on the Code Project

Sonork ID 100.9786 voidmain
www.busterboy.org

Derek Waters12-Feb-02 17:02

Derek Waters

12-Feb-02 17:02

To do so, you would need to update you main icon resource. If this is what you're after, you might want to check out:

BeginUpdateResource()
UpdateResource()
EndUpdateResource()

on MSDN. You'll need to use them to change your icon dynamically.

------------------------
Derek Waters
derek@lj-oz.com

Re: change application icon

moliate12-Feb-02 17:22

moliate

12-Feb-02 17:22

That is a lot harder. May be impossible. A possible solution might be to spawn a new process when the application is about to terminte. The process kills its parent, opens the parents .exe file, finds the icon and replaces it before terminating.

I really don't know if it will work. If the iconswapping is critical for your application you might give it a shot. As Derek pointed out you can use the resource function set.

/moliate

12-Feb-02 18:42

Icon must be stay changed after close application (In Explorer - another icon).

Changing View

12-Feb-02 13:57

Hi,

I wanna ceate an SDI app with a CEditView or CHtmlView in it, and change between them per buttonclick.
The only thing I don't know is how to begin and then how to continue.

Would you help me, please?
Thank you.

Recaro

Re: Changing View

Roger Allen13-Feb-02 2:56

Roger Allen

13-Feb-02 2:56

You should be able to do this by getting a pointer to the view you want to activate. Then gets its container child window and call MDIActivate() on it.

CView *pView  = ... ; // your view pointer
CChildWnd *pChild = (CChildWnd*)pView->GetParent() ;

pChild->MDIActivate() ;

Roger Allen
Sonork 100.10016

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MFC: Multi-threaded DLL Errors & Related Syntax :: C++

valikac12-Feb-02 13:33

valikac

12-Feb-02 13:33

Hi.

I am studying MFC from Jeff Promise's book. I had problems compiling the first sample MFC program from Prosis because I need to set the project from "single-threaded" to "multi-threaded."

First, "multi-threaded" works, but the execute is huge, maybe five-folds from my biggest win32 console program with many more lines of code. The size of "multi-threaded" un debug mode was 1.5mb. There are less than 100 lines of code. I tried to set "multi-threaded" to "multi-threaded DLL," but then Visual C++ would not compile the source . It responded with a bunch of errors. Do I need to install anything before using the multi-threaded DLL mode?

How does MFC works as far as software release? Let say I give the MFC program to a friend. Will the friend be able to run it? Is MFC/C++ similar to Java and VB where the program comes require specific system DLL?

Lastly, Promise's book is exceptional because it touches everything about MFC. I found some MFC syntax that are not like C++ (or maybe it is just my inexperience). For example, some derived functions return "BOOL" and "TRUE." I know C++'s "bool" and "true." I replaced "TRUE" with "true," and that worked okay. However, Visual C++ came up with errors when I replaced "BOOL" with "bool." Are syntax like th ones above MFC specific and are required?

Kuphryn

Re: MFC: Multi-threaded DLL Errors & Related Syntax :: C++

Nish Nishant12-Feb-02 13:44