Re: import a class from dll - C / C++ / MFC Discussion Boards

c_jangid12-Mar-06 19:56

12-Mar-06 19:56

hi there,
does anyone know how to create an SDI document in an ATL COM Dll?
I've created the three classes (derived from CDocument, ChtmlView, CframeWnd). the window is not created.
can anyone help.... ?

shekhar

Re: creating SDI Document in ATL COM

Hamid_RT12-Mar-06 20:18

Hamid_RT

12-Mar-06 20:18

Hi,c_jangid
Do you get error?

Re: creating SDI Document in ATL COM

c_jangid13-Mar-06 0:02

c_jangid

13-Mar-06 0:02

hi there,
i dont get any compilation error but i do get a runtime error. "Assertion failed".
i could find that the error is somewhere in the CSingleDocTemplate constructor. it doesn't return a valid pointer.
waiting for reply.
thanks...

import a class from dll

Naveen12-Mar-06 19:42

Naveen

12-Mar-06 19:42

Hi,
i have created a dll and exported a class. I want to import that class to another application. But how can i import that class with out using the lib file. We can import a function using GetProcAddress() api. Can i use this api to import the class?

Thanks in advance

nave

Re: import a class from dll

Nibu babu thomas12-Mar-06 20:07

Nibu babu thomas

12-Mar-06 20:07

Naveen R wrote:
Can i use this api to import the class?

No.

But there is a workaround...

Use this API to get the address of a function that returns an instance of the class that you wish to access dynamically.

For eg:

The function will be something like this...

void* FUNC_EXPORT CreateInstance()
{
	return static_cast< void*> (new SomeClass);
}

Use GetProcAddress to get the address of this function.

Nibu thomas
Software Developer

Re: import a class from dll

Naveen12-Mar-06 20:28

Naveen

12-Mar-06 20:28

For that i have to modify the dll isn't it? That's not possible

nave

Re: import a class from dll

Nibu babu thomas12-Mar-06 20:57

Nibu babu thomas

12-Mar-06 20:57

Naveen R wrote:
For that i have to modify the dll isn't it?

Yeah.

Nibu thomas
Software Developer

Re: import a class from dll

Ryan Binns12-Mar-06 21:55

Ryan Binns

12-Mar-06 21:55

If you know the C++ mangled name of the methods, you can. It's not very fun and depends on which compiler the DLL was compiled with.

You said you created the DLL, so why can't you use the lib file that was created with it?

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: import a class from dll

Naveen12-Mar-06 22:27

Naveen

12-Mar-06 22:27

What the problem is there are two dlls.
A class in the first dll is used by a second dll and a class in the second dll is used the first dll creating a cirular dependency.

So to avoid this i decided to load the class dynamically.
please tell me how can i load the class if i know the mangled name of class

nave

Re: import a class from dll

Ryan Binns12-Mar-06 22:33

Ryan Binns

12-Mar-06 22:33

Naveen R wrote:
A class in the first dll is used by a second dll and a class in the second dll is used the first dll creating a cirular dependency.

Bad idea. Fix your DLLs. What you're proposing to do is a hack around the real problem. DLLs should never rely on each other.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: import a class from dll

Naveen12-Mar-06 22:49

Naveen

12-Mar-06 22:49

ok i agree. Just for knowing can u tell me how can i load the class as u said?

nave

Re: import a class from dll

Ryan Binns12-Mar-06 22:55

Ryan Binns

12-Mar-06 22:55

Well, if you know the mangled names of all of the methods, you can use GetProcAddress() to get all the method addresses. Just remember that they have an extra parameter at the beginning - the this pointer.

I would strongly recommend that you never do this. It's a horrible hack and prone to lots of problems.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Driver Licence test in VC++

Gourav Agarwal12-Mar-06 18:48

Gourav Agarwal

12-Mar-06 18:48

hello friends ther is one problem with me that as i am an B.Tech (CS) student and i hav only 1 month to complete my project so kindly help me out to just guideline me how to implement the licensing software. actually i am working for the project, this project is totally assine to me . in the i hav to design the "Computerization of the driver livensing system" . in this few of the important forms are
1: login form
2) option window(tempory license/[permanent license)
3) user entry form(the driver comming for the first time. the whole detail like name,age,tell no been stored on the data base)
4) then we have the question test in which we have to show the objective type question in the random manney these Q r in the data base.
5) evaluation form (the performance of the test accorking to that driver is been shown and stored back in the data base)

. please look after the matter and kindly help me out or if you can / or if you hav a bit free time for me then please write code so that i can submit my project as soon as possible as days left are very less so . reply me soon ASAP

write me an mail to my ID at male_IIT@hotmail.com

gourav

Re: Driver Licence test in VC++

normanS12-Mar-06 23:34

normanS

12-Mar-06 23:34

Wow - others have voted you down, but I get to be first to tell you:
* CodeProject members will answer queries when you post code
* CodeProject members will not do all your homework for you.

I suggest you try doing it yourself for a week or two, then ask for help with the bits which don't work correctly.

how to return a string from COM DLL

Mann Khine12-Mar-06 17:55

Mann Khine

12-Mar-06 17:55

I 've one function that 's written with COM DLL.
I want to return a string from that function.
function declaration is like that

STDMETHODIMP CMyClass::Command()

from that function how can I return a string.

thanks in advance.

Re: how to return a string from COM DLL

Stephen Hewitt12-Mar-06 18:03

Stephen Hewitt

12-Mar-06 18:03

In the .IDL (or ODL file) change the declaration so it looks something like this:

HRESULT Command([out, retval] BSTR *pOut);

Now the function should look like this:

STDMETHODIMP CMyClass::Command(BSTR *pOut)
{
     if ( pOut == NULL )
     {
         return E_POINTER;
     }
 
     *pOut = SysAllocString(L"Your string here!");
     return S_OK;
}

If you're not familiar with BSTRs you should read up on them.

Steve

How to write memory Bitmap to BMP file directly?

FleetAdmiral12-Mar-06 16:18

FleetAdmiral

12-Mar-06 16:18

There are some data to be analyzed, and draw the result as a figure. I want to draw the result in memory firstly and then save the memory BMP to a file directly, not to show it on screen. How can I do that.

Note: I want to achieve all in dialog, not Doc/View framework.

By the way, the resulted BMP may large than the sreen.

Thanks a lot!

-- modified at 23:57 Sunday 12th March, 2006

Re: How to write memory Bitmap to BMP file directly?

includeh1012-Mar-06 16:40

includeh10

12-Mar-06 16:40

if u use memory DC, 2 suggestions:
1. bad one.
use GetPixel() to get color of a pixel - scan whole image - so u can have bitmap bits then save ur bitmap.
2. good one
I remember we can Create Bits section for memory DC (not sure), so bitmap bits can be read directly from memory DC.

anyway, u have to know file format of bitmap.

A nice tool for optimizing your Microsoft html-help contents.

Includeh10

Re: How to write memory Bitmap to BMP file directly?

Naveen12-Mar-06 16:51

Naveen

12-Mar-06 16:51

Please check http://www.codeproject.com/bitmap/drawing2bitmap.asp[^]

nave

Re: How to write memory Bitmap to BMP file directly?

FleetAdmiral12-Mar-06 17:41

FleetAdmiral

12-Mar-06 17:41

But I don't want to show the BMP on screen!

Re: How to write memory Bitmap to BMP file directly?

Hamid_RT12-Mar-06 17:43

Hamid_RT

12-Mar-06 17:43

Hi FleetAdmiral,
(I think you can change CreateCompatibleDC to createDC)

HDC hdc= CreateCompatibleDC(GetDC()->m_hDC);
HBITMAP hBitmap=CreateCompatibleBitmap(GetDC()->m_hDC,Width,Height);
SelectObject(hdc,hBitmap);

//Here you can from handle hdc
TextOut(hdc,150,150,"Hello",lstrlen("Hello"));

hBitmap=(HBITMAP)SelectObject(hdc,hBitmap);
CImage Image;
Image.Attach(hBitmap);
Image.Save("c:\\test.bmp");
Image.Detach();
DeleteDC(hdc);
DeleteObject(hBitmap);

Re: How to write memory Bitmap to BMP file directly?

Naveen12-Mar-06 18:15

Naveen

12-Mar-06 18:15

if u dont want to show it in screen , u can create a memory dc and draw the bitmap to that dc.Then while saving to file, pass the bitmap object of this memory dc.

nave

-- modified at 0:21 Monday 13th March, 2006

any comment to display the arrangement?

includeh1012-Mar-06 15:48

includeh10

12-Mar-06 15:48

an int array, assume length is 10:
int ary[10];

now i need to display all of them - 5 of them every time as arrangement - no repeat, no missing.

i.e.
ary[0],ary[3],ary[6],ary[7],ary[8]
is one of them to be displayed.

any idea?

A nice tool for optimizing your Microsoft html-help contents.

Includeh10

Re: any comment to display the arrangement?

Anilkumar K V12-Mar-06 19:34

Anilkumar K V

12-Mar-06 19:34

What u mean by this???
>>>>> 5 of them every time as arrangement - no repeat, no missing.

help needed urgently

rahulmballal12-Mar-06 14:38

rahulmballal

12-Mar-06 14:38

Hi,
I am new to VC++, I just need to know how to print something in the child view that i have stored in the document class?? cn i use the archive object??

please help me wid this one

rMb

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.