How do I do this? - C / C++ / MFC Discussion Boards

Dimitri Rochette1-Oct-02 11:44

1-Oct-02 11:44

If you want to allocate memory in a Dll and free this memory elsewhere you can use a GlobalAlloc / GlobalFree ( with the GMEM_FIXED flag you only have to change the alloc and the free lines ).

problem with pasting bitmap to the clipboard under win98

Mariusz Popiolek1-Oct-02 10:49

Mariusz Popiolek

1-Oct-02 10:49

Hi
I issued this problem week ago but I still haven't solved it. Now I know a bit more about the nature of the problem. I created MFC program (dialog application) and I'm trying to execute such code:

	CBitmap Bitmap;<br />
	int a = 0;<br />
	SetLastError(0);<br />
	a =	GetLastError();<br />
	if( !Bitmap.LoadBitmap( IDB_BITMAP1 ) ) MessageBox("loadbitmap");<br />
	a =	GetLastError();<br />
	SetLastError(0);<br />
	if( !OpenClipboard() ) MessageBox("openclipboard");<br />
	a =	GetLastError();<br />
	SetLastError(0);<br />
	if( !EmptyClipboard() ) MessageBox("emptyclipboard");<br />
	a =	GetLastError();<br />
	SetLastError(0);	<br />
	if( !SetClipboardData( CF_BITMAP, Bitmap ) ) MessageBox("setclipboarddata");<br />
	a =	GetLastError();<br />
	SetLastError(0);<br />
	if( !CloseClipboard() ) MessageBox("closeclipboard");<br />
	a =	GetLastError();<br />
	SetLastError(0);<br />
//my debugging code maybe looks a bit strange and silly, but it works :)<br />

Everything works perfect under Win2000, but under Win98 not, so I installed VC6.0 under Win98 to examine the problem. I don't get any runtime errors, program executes smoothly, but when I try to paste from clipboard (in Paint) nothing appears. When I execute my code for second time Paint shows message "Error in acquiring data from clipboard" (that's my translation from polish version of Windows, so it can be a bit different in english version). Someone advised me to empty clipboard before pasting but it doesn't help Frown | :(

Anyone have any clue (this is quite urgent unfortunately). Thanks in advance.

Greetings
Mariusz Popiolek

Re: problem with pasting bitmap to the clipboard under win98

Mariusz Popiolek1-Oct-02 11:27

Mariusz Popiolek

1-Oct-02 11:27

I discover something. This problem is not connected with clipboard. When I tried to use Bitmap in another way (I made a Static of type bitmap) it also didn't work, but of course on Win2000 it works:

m_Image.SetBitmap( Bitmap );

Static image is changing on Win2000, on Win98 nothing happens. I don't have any idea Frown | :(

greetings
Mariusz Popiolek

Re: problem with pasting bitmap to the clipboard under win98

Tomasz Sowinski1-Oct-02 11:42

Tomasz Sowinski

1-Oct-02 11:42

In your previous example, 'Bitmap' variable was local. And CBitmap destructor deletes the bitmap, so handle passed to m_Image becomes invalid.

What happens on W2K when you invalidate the static window? Does it still show the picture?

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

Re: problem with pasting bitmap to the clipboard under win98

Mariusz Popiolek1-Oct-02 12:13

Mariusz Popiolek

1-Oct-02 12:13

You are right! But I found this solution on my own Smile | :)

when I remembered that it helped a time ago when I was trying to set icons in a CTreeCtrl (of course it was your hint if I remember well, thanks once again). After invalidation picture dissapears on Win2000. When I made Bitmap global on win98 finally bitmap works properly. Thanks anyway, but do you know why this problem occurs (I mean why Win98 behaves different from Win2000 in such basic thing in my opinion).

Greetings
Mariusz Popiolek

Re: problem with pasting bitmap to the clipboard under win98

Tomasz Sowinski1-Oct-02 12:18

Tomasz Sowinski

1-Oct-02 12:18

Mariusz Popiolek wrote:
mean why Win98 behaves different from Win2000 in such basic thing

Probably W2K invalidates/updates window right after STM_SETIMAGE.

So you were able to fix the problem with clipboard as well?

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

Re: problem with pasting bitmap to the clipboard under win98

Mariusz Popiolek2-Oct-02 0:22

Mariusz Popiolek

2-Oct-02 0:22

Yes, after a long period of time (I noticed this issue on previous sunday I suppose), but I wasn't really trying to solve it Smile | :)

(I was doing more urgent things, but finally I had to fix it). Now my VBA program works correctly on Win98 and Win2000 (I'm using clipboard to create custom toolbar icons in MSOffice, as far as I know that's the only way and the first thought which came to my mind was to do this in dll, so I can combine bitmaps in one dll).

Greetings
Mariusz Popiolek

How do I do this?

Anonymous1-Oct-02 9:31

Anonymous

1-Oct-02 9:31

I defined 2 classes - A and B;

class A {
public:
B GetB() {
return B();
}
};

class B {
public:
A GetA() {
return A();
}
};

since both classes make use of eachother, i get an "error C2501: 'A::B' : missing storage-class or type specifiers" when I try to compile.

Is this sort of thing supported with C++?

Re: How do I do this?

Nick Parker1-Oct-02 9:40

Nick Parker

1-Oct-02 9:40

Someone else may give a better example but this is possible through inheritance.

class A
{
protected:
   int Age;
   int GetAge()
   {
      return Age;
   }
};

class B:A
{
 int f;
 void Foo(); 

};

Access to the variable Age is available as B inherits A

//===========
B b;
b::A.Age;

Nick Parker

The goal of Computer Science is to build something that will last at least until we've finished building it. - Unknown

Re: How do I do this?

Scott H. Settlemier1-Oct-02 9:51

Scott H. Settlemier

1-Oct-02 9:51

use a forward declaration:

class B;

class A
{
public:
   B GetB();
};

class B
{
public:
   A GetA();
};

and put implementation in the .cpp file

Re: How do I do this?

Michael Dunn1-Oct-02 9:47

Michael Dunn

1-Oct-02 9:47

The class B isn't defined at the point you're trying to use it:

class A {
public:
  B GetB() { return B(); } <font color=red>// class B not defined here</font>
};

thus you get the error. Add a forward declaration of B so the compiler knows what it is:

class B; // forward declaration
 
class A { ...

--Mike--
Just released - 1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Re: How do I do this?

PJ Arends1-Oct-02 9:47

PJ Arends

1-Oct-02 9:47

use a forward declaration of class B.

class B; // forward declaration

class A
{
public:
    B GetB() {
...
}

class B
{
   A GetA () {
...
}

CPUA 0x5041

Sonork 100.11743 Chicken Little

"So it can now be written in stone as a testament to humanities achievments "PJ did Pi at CP"." Colin Davies

Within you lies the power for good - Use it!

Re: How do I do this?

Mariusz Popiolek1-Oct-02 9:52

Mariusz Popiolek

1-Oct-02 9:52

At the point where you define class A compiler knows nothing about identifier B, that's why error occurs. Put this before declaration of A:
class B;
Now compiler knows that B is a class, but that's not all. To return B from function compiler must know declaration of B, so you have to return pointer to B, not object B(when compiler see pointer to class, it doesn't have to know declaration of this class). Also you can't call constructor of B at this point, so just declare function in a class A and make a definition after a declaration of class B.

Greetings
Mariusz Popiolek

Re: How do I do this?

Scott H. Settlemier1-Oct-02 10:00

Scott H. Settlemier

1-Oct-02 10:00

LOL!

It's like a whole class full raising their
hands all at once 'cause it's one of the
answers everyone has just waiting for an
opportunity to get out.

Re: How do I do this?

PJ Arends1-Oct-02 10:15

PJ Arends

1-Oct-02 10:15

Yeah well, what can I say. It was an easy question and I need to get my post count up a little Big Grin | :-D

Re: How do I do this?

Mariusz Popiolek1-Oct-02 10:15

Mariusz Popiolek

1-Oct-02 10:15

When I have seen this question there wasn't any answers, but when I finished answering the post(I tried the code in VC to be sure if it's working), there was already plenty of answers Smile | :)

.

Greetings
Mariusz Popiolek

Re: How do I do this?

Roger Stewart1-Oct-02 10:00

Roger Stewart

1-Oct-02 10:00

To avoid this error, you can 'forward declare' class B.

class B;

class A
{
public:
   B GetB() { return B(); }
};

class B
{
public:
   A GetA() { return A(); }
};

Roger Stewart
"I Owe, I Owe, it's off to work I go..."

Re: How do I do this?

Anonymous1-Oct-02 11:05

Anonymous

1-Oct-02 11:05

thanks every one

clistctrl::getitmeText

pnpfriend1-Oct-02 9:07

pnpfriend

1-Oct-02 9:07

I have listctrl with rows(vary) and 3 column
let say first column is a,second is b, third is c;
I want the data of a, b, and c of the row.
so i tried the following ways

<br />
for(int i=0;i<numberOfRow;i++) //<br />
{<br />
CString dataA = myListCtrl.GetItemText(i,0);<br />
CString dataB = myListCtrl.GetItemText(i,1);<br />
CString dataC = myListCtrl.GetItemText(i,2);<br />
<br />
// anothe method<br />
LV_ITEM lvitem;<br />
ZeroMemory(&lvitem, sizeof(lvitem));<br />
lvitem.mask = LVIF_TEXT | LVIF_STATE;<br />
lvitem.iItem = nIndex[i]; <br />
lvitem.iSubItem = 1; <br />
myListCtrl.GetItem(&lvitem); <br />
<br />
dataA = lvitem.pszText;<br />
}<br />

both ways gave me let say dataA value as junk. How can I get back my item text???

Thanks

Re: clistctrl::getitmeText

Michael Dunn1-Oct-02 9:50

Michael Dunn

1-Oct-02 9:50

Can't say why the first way is failing, but the second doesn't work because you're not providing a buffer for the control to store the text in. You need to set pszText and cchTextMax to the address and size of the buffer before calling GetItem().

--Mike--
Just released - 1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Re: clistctrl::getitmeText

pnpfriend2-Oct-02 5:43

pnpfriend

2-Oct-02 5:43

let me try
Thanks Michael

how to give the catch block a filename?

ns1-Oct-02 9:06

1-Oct-02 9:06

If theres a problem with file strFile0 and an exception is thrown, I want the error message to have the name of the faulty file. This name is gotten in the try block. I dont think I can pass it in the catch argument:

catch(CFileException e, strFile0)
		
		{

			CString temp;

			temp.Format("Error opening file  : %d", e.m_cause);
			AfxMessageBox(temp);

			return -1;
		}
}

So how do I communicate it to my messagebox in the catch block?

Appreciate your help,
ns

Re: how to give the catch block a filename?

jmkhael1-Oct-02 9:08

jmkhael

1-Oct-02 9:08

catch(CFileException e, strFile0)

{

CString temp;

temp.Format("Error opening file : %d ", e.m_cause);
AfxMessageBox(temp + e.m_strFileName);

return -1;
}

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

Re: how to give the catch block a filename?

ns1-Oct-02 9:13

1-Oct-02 9:13

Thats convenient! You did however mean to remove the strFile0 argument I was trying to pass in, right ? I am off to look up CFileException and see what all it exposes... Smile | :)

Many thanks,

Appreciate your help,
ns

Re: how to give the catch block a filename?

jmkhael1-Oct-02 9:14

jmkhael

1-Oct-02 9:14

Yeah that way, i mean if u correct ur own mistakes u wont ever make them again Smile | :)

For ur own good (ok, i forgot Smile | :)

)

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

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