Managed C++/CLI

6-Jan-06 4:51

bikshamaiah.g wrote:
what is the windowes services in vb.net

This question would be most appropriate for the Visual Basic / VB.NET[^] forum.

Regards,
Nish

C++

S.E5-Jan-06 21:54

S.E

5-Jan-06 21:54

hi,
Can anybody help me as I need a sample code for taking in data in C++ and then writting it into textfile

Regards,

Re: C++

Yuwraj5-Jan-06 23:00

Yuwraj

5-Jan-06 23:00

you can take data in a variable by cin

and print that data to output stream by cout.

or

u can use file opration for it.

Create file,write data to file and finaly read data from file. Big Grin | :-D

Re: C++

Nish Nishant6-Jan-06 4:11

6-Jan-06 4:11

See this article :-

How to: Write Text to a File[^]

Regards,
Nish

Re: C++

Nish Nishant6-Jan-06 4:12

6-Jan-06 4:12

Note that the samples are in C# and VB, but it's trivial to convert that to C++/CLI.

Regards,
Nish

Question on Hashtables

jblau5-Jan-06 17:43

jblau

5-Jan-06 17:43

My understanding of Hashtables is this: If I declare a Hashtable like so: Hashtable *hashMyHashtable = new Hashtable; I don't need to have a corresponding DELETE after having used the NEW for the Hashtable. The reason being that the Hashtable is a Managed object and so I don't need to Delete it in my destructor.

My question is this: If I store an object that was declared with a NEW, and store it in the hashtable, do I need to go back through the hashtable and delete those objects, or does the managed code do that as well?

Example:
MyObject *tempObject = new MyObject;
Hashtable *hashObjects = new Hashtable;

hashObjects->Add(key, tempObject);

So if I store several tempObjects in my hashtable, do I need to traverse through the hashtable and DELETE the tempObjects, or does the garbage collector handle this as well as the hashtable itself?

If I do need to delete them, will a call to hashObjects->clear(); delete the objects?

Thanks,

Jody Blau

J. Dunlap5-Jan-06 18:53

J. Dunlap

5-Jan-06 18:53

The correct way to work with managed objects in C++/CLI is to use managed references, and the gcnew operator.

//note the "^", which denotes a managed reference, just as a "*" denotes a pointer,
//and the use of the gcnew operator to instantiate the objects on the managed heap.
MyObject^ tempObject = gcnew MyObject();
Hashtable^ hashObjects = gcnew Hashtable();

hashObjects->Add(key, tempObject);

Once all references to a managed object are set to null or go out of scope, the object will be garbage collected at whatever point the CLR decides to do so.

Nish Nishant6-Jan-06 2:43

6-Jan-06 2:43

Justin

I believe he's using the now obsolete MC++ syntax.

Michael Dunn5-Jan-06 22:53

Michael Dunn

5-Jan-06 22:53

jblau wrote:
do I need to go back through the hashtable and delete those objects

No, and you can see this by counting the references to the objects.

MyObject* tempObject = new MyObject;

The ref count on the object is now 1.

hashObjects->Add(key, tempObject);

The hash table now holds another reference on the object, so the ref count is 2.

Once the tempObject object falls out of scope, the ref count drops to 1. When you empty the hash table, it releases the references on the objects that were in the table, so the ref count drops to 0.

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | NEW!! PimpFish | CP SearchBar v3.0 | C++ Forum FAQ
Laugh it up, fuzzball.

Nish Nishant6-Jan-06 2:44

6-Jan-06 2:44

To add to what Mike says, the objects that you add to the hash table are also managed objects, and thus garbage collected.

If you add unmanaged pointers to the hashtable, you'd have to manually delete the native objects that are pointed to by those pointers.

How to use &quot;graphic.h&quot; in visual C++?

m-khansari5-Jan-06 10:02

m-khansari

5-Jan-06 10:02

I want to use graphic header in visual c++
but it's not possible.
please help me.
great tanks to you.
Bye.
MK4

-- modified at 16:04 Thursday 5th January, 2006

Re: How to use &amp;quot;graphic.h&amp;quot; in visual C++?

Nish Nishant5-Jan-06 10:37

5-Jan-06 10:37

In what way is it not possible? Do you mean it's not available? If so, there's nothing you can do about it. On the other hand, if you copied it from a Borland C++ installation, and it's not compiling, then you might have to change the Borland specific macros/code to use Microsoft specific or generic syntax.

Re: How to use &amp;amp;amp;quot;graphic.h&amp;amp;amp;quot; in visual C++?

m-khansari6-Jan-06 19:37

m-khansari

6-Jan-06 19:37

Hi tanks for ur answer
i want to compile some programs used the graphics.h with visual C++ 6.
and i don't know about how the graphics.h works to change it.
please help me.
bye. Blush | :O

MK4

-- modified at 1:49 Saturday 7th January, 2006

Re: How to use &quot;graphic.h&quot; in visual C++?

Sheng Jiang 蒋晟6-Jan-06 8:15

Sheng Jiang 蒋晟

6-Jan-06 8:15

if you have the TC2 graphic.h headers and libs you should able to compile it with VC1.5 ...

My blogs:

http://blog.joycode.com/jiangsheng
http://blog.csdn.net/jiangsheng
http://bloglines.com/public/jiangsheng

Command what is yours
Conquer what is not
---Kane

MOVED

tj_cts5-Jan-06 8:28

tj_cts

5-Jan-06 8:28

MOVED TO VISUAL C++
http://www.codeproject.com/script/comments/forums.asp?msg=1326246&forumid=1647#xx1278597xx
-- modified at 15:01 Thursday 5th January, 2006

Re: Get Status of Comm Port

Nish Nishant5-Jan-06 8:42

5-Jan-06 8:42

This question should be posted in the Visual C++[^] forum. This is the C++/CLI forum that's dedicated to the new managed and mixed-mode compiler available in VC++ 2005.

Re: Get Status of Comm Port

tj_cts5-Jan-06 8:59

tj_cts

5-Jan-06 8:59

Will Do.

Thanks Much!

T.J. Barbour

How to create a CFileDialog appearance resource?

doctorpi2-Jan-06 22:02

doctorpi

2-Jan-06 22:02

Hi guys
I've seen some articles talking about CFileDialog with preview and the CFileDialog resource is bigger than the usual CFileDialog. I read about "template dialog" but I don't know how this stuff is implemented.
What is the procedure to do a custom "CFiledialog" resource?
Thanks and Happy New Year
Doc

Re: How to create a CFileDialog appearance resource?

Nish Nishant3-Jan-06 6:08

Re: How to create a CFileDialog appearance resource?

3-Jan-06 6:08

This question should be posted in the Visual C++[^] forum. This is the C++/CLI forum that's dedicated to the new managed and mixed-mode compiler available in VC++ 2005.

doctorpi3-Jan-06 21:03

doctorpi

3-Jan-06 21:03

Sorry

submission

thekeralite2-Jan-06 15:56

thekeralite

2-Jan-06 15:56

is it possible to publish my cpp program code in this website ? does the code have to meet some specifications/standard ? how do i submit it ?

Re: submission

Nish Nishant3-Jan-06 6:09

Re: threads and Managed c++

3-Jan-06 6:09

thekeralite wrote:
is it possible to publish my cpp program code in this website ? does the code have to meet some specifications/standard ? how do i submit it ?

Please see our Submission Guidelines[^]

threads and Managed c++

Roy K2-Jan-06 15:02

Roy K

2-Jan-06 15:02

Hello,
I am making a windowed application and need the program to sit in a loop waiting to receive messages. I am having some trouble with the thread. Here is the code I have now...

Form1 * messageThread;
messageThread = new Form1;
ThreadStart * pThread = new ThreadStart(messageThread, &Form1::messageLoop);
Thread *oThread = new Thread(pThread);
oThread->Start();

This code compiles fine, but I don't think it works correctly. This is my first experience with threads, so I would appreciate any input. This code is executed when a button is clicked. I want it to call the messageLoop function, which is in Form1. When the thread receives a message, I want it to output it to the gui - but it does not do this. Any thoughts?
Roy K

Nish Nishant3-Jan-06 6:11