C / C++ / MFC

8-May-03 0:50

Greetings. I'm using a VC++ 6.0 MDI to call a VC# form .dll. I exposed the VC# dll as a COM interface... n now I need to tell the VC# dll who's the daddy... but the VC# forms daddy should be a System.Windows.Forms.Form()... So i want to pass the handle of the VC++ 6.0 MDI app to a method from the VC#... it asks for an IUnknown... Please tell me how do i take the this->m_hWnd pass it through an IUnknow* and finally put it in a System.Windows.Forms.Form object... can this b done? is there a more friendly way? Thanks Confused | :confused:

NHM

Stephane Rodriguez.8-May-03 1:01

8-May-03 1:01

If the only thing you need to pass is a window handle, then ::SendMessage(...) is probably the fastest way to achieve it. It does not require the COM interop you have mentioned.

NHM8-May-03 1:19

8-May-03 1:19

how can the VC# dll receive messages... in vc++6.0 PreTranslateMessage is the answer... n in VC#? Confused | :confused:

Stephane Rodriguez.8-May-03 1:29

8-May-03 1:29

NHM wrote:
how can the VC# dll receive messages... in vc++6.0 PreTranslateMessage is the answer... n in VC#?

A Windows Forms app has a UI thread which processes windows messages just like any WIN32 app with a message loop. Any Windows Form control has a virtual WndProc method that can be overridden to respond accordingly.

The other way, a C# app can send a WIN32 message to any window (for instance a window from a VC++6 app) by using the [DllImport] P/Invoke technique :

[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);

NHM8-May-03 3:18

8-May-03 3:18

if i override WndProc in the windows form (C# dll) then when i try to open it through the VC++ 6.0 App it stops execution... just gives a runtime error... ideas? thanks 4 your suport .S.Rod!

Stephane Rodriguez.8-May-03 3:29

8-May-03 3:29

NHM wrote:
when i try to open it through the VC++ 6.0 App

What do you mean ?

Has it anything to do with the debug session ? Do you mean you are trying to access the C# WndProc implementation from your VC++ debug session ? No need to go further, you simply can't.

Or do you mean you are processing the message in the C# wndproc implementation and then it fails? If the code fails at this point, then it might be helpful for those listening if you post the code.

NHM8-May-03 3:45

8-May-03 3:45

i've just overriden the WndProc... no code added to the base override...

this is what i have...

a) a vc++ 6.0 Mdi app (.exe)
b) a vc# dll with:
- class A (interface) (cominterop)
(i have to call some methods and access some properties)
- class B (windows form)

in the vc++ 6.0 mdi app i create an instance of classA
then i call a method from class A wich does this:

public void SomeThing()
{
Form1 f = new Form1();
f.Show();
}

and this is what i intended to do:

public void SomeThing( Form parent)
{
Form1 f = new Form1( Form parent);
f.MdiParent = parent;
f.Show();
}

i just want to say to the VC# winForm that his container is the VC++ 6.0 APP

what can i do?

Stephane Rodriguez.8-May-03 3:51

Re: WS_CLIPSIBLINGS.........

8-May-03 3:51

The simplest thing that comes to my mind is to reparent the C# form window.
This can be done with simple things :
- the window handle of the C# form is obtained using this.Handle if you use managed code. Otherwise, from C++ code you can enum windows or use FindWindow(...) with a particular caption to get that window handle.
- then, use WIN32 ::SetParent(hwndForm, hwndNewParent /*MDIapp frame window hande*/) to reparent the form.

Good luck!

WS_CLIPSIBLINGS.........

Neha8-May-03 0:15

Neha

8-May-03 0:15

Hi,

I have a image control(child of main window) in a window,which is created with WS_CLIPSIBLING flag.
But when i move some other window over my main window. image control receives WM_PAINT message. How can i avoid receiving the WM_PAINT message for the image control?

jhaga8-May-03 2:59

jhaga

8-May-03 2:59

I dont know any way to avoid recieving WM_PAINT but
you can ignore (comment code out) where you handle
the message.

jhaga

CFile

macmac387-May-03 23:19

macmac38

7-May-03 23:19

Why this generates "test.pmjaaaaYYYYY" as output??

  <br />
<br />
<br />
<br />
<br />
   char* szBuffer = NULL;<br />
   int i = 0;<br />
<br />
   CFile f;<br />
          <br />
   if( f.Open ("F:\\test\\id.txt", CFile::modeRead ) ){  <br />
	   try {                           // Get the size of the file.    <br />
		   i = f.GetLength();        // Create buffer to hold filedata.    <br />
		   szBuffer = new char[i];   // Read in the file data <br />
		      <br />
		   if(szBuffer != NULL)<br />
			   <br />
		   f.Read(szBuffer, i);       <br />
		   f.Close();                  // Close the file. <br />
<br />
            } <br />
	   <br />
	   catch (CFileException *e)  <br />
	   {    <br />
		   AfxMessageBox ("Error!");    <br />
		   e->Delete();  <br />
	   } // end TRY-CATCH<br />
<br />
   } // end IF<br />
   <br />
     CString csPath = szBuffer;<br />
	  <br />
     SaveStream(csPath);<br />
<br />
	 if(szBuffer != NULL)  <br />
          delete [] szBuffer;<br />

Thanks, Mark

Neville Franks8-May-03 0:08

Neville Franks

8-May-03 0:08

The file you are reading won't have a 0 terminator. Try:

szBuffer = new char[i+1]; // Read in the file data 
szBuffer[i] = 0;

Neville Franks, Author of ED for Windows. www.getsoft.com
Make money with our new Affilate program

macmac388-May-03 0:36

macmac38

8-May-03 0:36

Now it works. Will a "Detected memory leaks!" be a problem?

Thanks, Mark

Neville Franks8-May-03 1:56

Neville Franks

8-May-03 1:56

macmac38 wrote:
Will a "Detected memory leaks!" be a problem?

Short answer, Yes.

Also if you are reading a fixed length file, you should write using fixed length routines, not a stream. ie, don't mix file i/o types unless you have to.

Neville Franks, Author of ED for Windows. www.getsoft.com
Make money with our new Affilate program

Hari Krishnan (Noida)8-May-03 0:46

Hari Krishnan (Noida)

8-May-03 0:46

Hi,
As, franks mentioned, it happens because, the output is not null-terminated. Here's the code snippet, which very well read your file, without any memory leaks.

-----------------------------------------------------------
CFile oFile;
DWORD dwFileLength;
if(oFile.Open("F:\\test\\id.txt", CFile::modeRead))
{
try
{
CString strBuffer;
dwFileLength = oFile.GetLength();
LPTSTR szBuffer = strBuffer.GetBufferSetLength(dwFileLength);

oFile.Read((LPVOID)szBuffer, dwFileLength);
oFile.Close();
CString csPath(strBuffer);
strBuffer.ReleaseBuffer();
}
catch(CFileException *e)
{
AfxMessageBox ("Error!");
e->Delete();
}
}
-----------------------------------------------------------

regards
~Hari~

Carray doubt

doctorpi7-May-03 22:38

doctorpi

7-May-03 22:38

Sorry if this is a silly question, but I'm a little confused.
I've got a class MyClass and I want to have a CArray of MyClass objects in the Doc class of my application.
Ex:
In CMyAppDoc
CArray <<cmyclass,cmyclass>> m_myArray;

My question is.
How I have to declare and have acces to the array to touch the values of it directly (by reference) in the view?
CMyAppView
?????

Best Regards
Dr. Pi

Dr-Kuulun7-May-03 22:54

Dr-Kuulun

7-May-03 22:54

Hi,

i had the same problem and it seems to be impossible.
i created a lot of instances of my class with 'new' and than i stored the pointers in an CObList or CObArray.
This array stores only the pointers, so clean the memory up ('delete pClass') when deleting the array.

Dr-Kuulun

Cedric Moonen7-May-03 22:57

Cedric Moonen

7-May-03 22:57

Try this:

CArray<CMyClass*,CMyClass*&> m_MyArray;

And to acces any data:

CMyClass* Temp = m_MyArray[i];<br />
Temp->DoSomething();

Hope this helps !
Ced

jhwurmbach7-May-03 23:15

jhwurmbach

7-May-03 23:15

You are probably better off using the standardized std::vector class:
std::vector< CMyClass > m_myArray;

... now you can fill the vector e.g. using push_back()...

And now you can use
CMyClass c = GetDocument()->m_myArray[0];
to access the first data item in the associated document.

Hope this helps

My opinions may have changed, but not the fact that I am right.