C / C++ / MFC

How to use C++ DLL in VS.NET 2005

23-Jul-07 20:58

hmm Are you handling any messages in the class - especially size-related ones?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: Multiple Window

Anu_Bala23-Jul-07 21:03

Anu_Bala

23-Jul-07 21:03

No,

In constructor i get the size of system window.(resolution)

CChildFrame::CChildFrame()
{
EnumDisplaySettings (NULL, ENUM_CURRENT_SETTINGS, &ESimSetDM);
}

BOOL CChildFrame::PreCreateWindow(CREATESTRUCT& cs)
{
// TODO: Add your specialized code here and/or call the base class

if( !CMDIChildWnd::PreCreateWindow(cs) )
return FALSE;

return TRUE;
}

Anu

galloping_stallion23-Jul-07 19:40

galloping_stallion

23-Jul-07 19:40

Hello,
I've just joined CodeProject.I have a C++ DLL written in dev-cpp IDE, but I can't use it in my .net project. Can anyone please suggest a way how to use in my VS.NET 2005.
I tried to use VS 6.0, I was able to create an application which uses the DLL and it succeeded.Then I made an ActiveX component in VS 6.0 to use in .net. Although the ActiveX component was successfuuly created, I couldn't use it in .net.How can I use that unmanaged dll in .net.
I get the error saying that it can't load it since it wasn't a valid COM component or activeX component.
If anyone has come across this issue please give me a suggestion.

Thanks and Regards

Re: How to use C++ DLL in VS.NET 2005

ashukasama25-Jul-07 3:05

ashukasama

25-Jul-07 3:05

Good document in MSDN

Interoperating with Unmanaged Code

http://msdn2.microsoft.com/en-us/library/sd10k43k(VS.71).aspx[^]

Passing a reference to a pointer

User 58385223-Jul-07 19:21

User 583852

23-Jul-07 19:21

One of my colleagues asked me to have a look at some of his code with him. In it he had a method that performed a lookup of an stl collection. If the key was found he retured pointers to two objects through references passed into the method.

bool FindSomethingAndSetThesePointers(const string& key, Class1 *&obj1, Class2 *&obj2);

I sugested that it was pretty unusual way of doing things and looked a little "smelly". When he pressed me on it I found it hard to give a good reason not to do things this way but I still feel a bit uneasy about it. What do you guys think?

ps I suggested that the reference be made a const and we both scratched our heads for a bit thinking where the const key word should go

Re: Passing a reference to a pointer

Arman S.23-Jul-07 20:06

Arman S.

23-Jul-07 20:06

Josh Gray wrote:
One of my colleagues asked me to have a look at some of his code with him. In it he had a method that performed a lookup of an stl collection. If the key was found he retured pointers to two objects through references passed into the method.

bool FindSomethingAndSetThesePointers(const string& key, Class1 *&obj1, Class2 *&obj2);

I sugested that it was pretty unusual way of doing things and looked a little "smelly". When he pressed me on it I found it hard to give a good reason not to do things this way but I still feel a bit uneasy about it. What do you guys think?

I don't think this is 'smelly'. Usually, we do such things when it is really needed. In this case, you should decide what you want to do with the pointers returned. If your collection holds pointers [to some objects], after returned these two pointers, you are able to modify the values of them and thus directly affect the pointers inside the collection. For example,

FindSomethingAndSetThesePointers(""somejey", p, q);

p = NULL;

this will set the corresponding element of the collection to NULL. So you were able to directly change the elements of the collection.

Anyway, if you do not need such freedom of changing the collection outside the FindSomethingAndSetThesePointers, then no need to Class*&, a simple Class* will do.

If your collection holds objects (not pointers to them), you may return either pointer to them, or reference to them, or even a copy of them (if you think it is appropriate).

bool FindSomethingAndSetThesePointers(const string& key, Class1 &obj1, Class2 &obj2);

Sometimes, choosing between Class *' and Class &' is either a matter of taste or a convention.

--
=====
Arman

Re: Passing a reference to a pointer

Cedric Moonen23-Jul-07 20:22

Cedric Moonen

23-Jul-07 20:22

Arman Z. Sahakyan wrote:
If your collection holds objects (not pointers to them), you may return either pointer to them, or reference to them, or even a copy of them (if you think it is appropriate).

I don't think this is a good idea: if the container is reallocated, your pointer will become invalid.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Passing a reference to a pointer

codeII23-Jul-07 23:44

codeII

23-Jul-07 23:44

This technique can be used to assign/reassign a pointer within a function.
Another way of doing this is a pointer to a pointer **.

exampl.

Void MyAllocFunction( TYPE*& pData )
{
delete [] pData;
pData = new TYPE[ x ];
}

TYPE* pData = NULL;
MyAllocFunction( pData );
delete [] pData;

From these methods I prefer a reference to a pointer for readability and error safety reasons.

Preferably a function which allocates a pointer has to destroy it; this keeps it clear what function is responsible for destruction. From this point of view you have to provide using both of these techniques.

VC 6.0 TO VC 8.0 POSTMESSAGE()

shakumar_2223-Jul-07 19:11

shakumar_22

23-Jul-07 19:11

HI
I DEVELOPED A VC++ PROGRAMME IN VC 6.0 AND IT WAS RUNNING AND OUT PUT WAS CORRECT.

WHEN I RUN THE SAME PROGRAMME IN VISUAL STUDIO 2005, THERE WAS NO COMPILE ERROR, BUT THER WAS AN OCCURING RUNTIME ERROR .

IN MY APPLICATION I USED POST MESSAGE(),POST THREAD MESSAGE().
THERE WAS AN ERROR ON POST THREAD MESSAGE (NOT ON POSTING BUT ON RECEIVING)

VC 6.0 : CString str; str.Format("%d",i);
THIS WAS WORKING IN V6.0 BUT NOT IN VISUAL STUDIO 2005.

GIVE YOUR SUGGESTION ON THIS

AWAITING FOR YOUR REPLY

REGARDS
SHAKUMAR

shakumar

Mark Salsbery23-Jul-07 19:25

23-Jul-07 19:25

What errors? What does not working mean?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

shakumar_2223-Jul-07 19:36

shakumar_22

23-Jul-07 19:36

HI
In Server socket OnAccept

if(Accept(Serversock)==1)
AfxmessageBox("Server Accepted");
else
AfxmessageBox("Server not Accepted");

On this code it does not showing "Server not Accepted" or "Server not Accepted"

But it was run cleraly in vc6.0.

shakumar

Mark Salsbery23-Jul-07 19:41

23-Jul-07 19:41

Wow. That has absolutely nothing related to your first post Smile | :)

All I can tell so far is that you have some debugging to do.

Your VC6 code compiles and links with no errors or warnings, right?

You mentioned recieving thread messages - the prototype for the ON_THREAD_MESSAGE handler function
changed. The return type is now void.

MArk

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

shakumar_2223-Jul-07 19:58

shakumar_22

23-Jul-07 19:58

Hi
Thanks for your Reply

As your suggestion ,
Returning type was changed to "Void" ok ther no error now.

But there was an Runtime error in OnAccept();
My programe was Socket programme,

Server Socket Created, Listening;
Client Socket Created, Connected to Server.

When Client Connect to Server Socket in Server Socket OnAccept() Function its get Run time Error.

CServer::OnAccept()
{
if(Accept(Serversock)==1)
AfxmessageBox("Server Accepted");
else
AfxmessageBox("Server not Accepted");
}

Awaiting for your reply

shakumar

Mark Salsbery23-Jul-07 20:05

23-Jul-07 20:05

shakumar_22 wrote:
When Client Connect to Server Socket in Server Socket OnAccept() Function its get Run time Error.

What error? If you run in the debugger and put a breakpoint at the start of CServer::OnAccept(),
does the breakpoint get hit? If so, and you single step through the code, where does the error
occur?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Rage24-Jul-07 1:41

Rage

24-Jul-07 1:41

Mark Salsbery wrote:
Wow. That has absolutely nothing related to your first post

The first post was some pain yeld by the CAPS LOCK key being hit.

http://www.readytogiveup.com/[^] - Do something special today.
http://www.totalcoaching.ca/[^] - Give me some feedback about this site !

Mark Salsbery24-Jul-07 4:43

Problem in GDI+ LinearGradientBrush

24-Jul-07 4:43

Rage wrote:
The first post was some pain yeld by the CAPS LOCK key being hit

I didn't even consider that!

Laugh | :laugh:

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Naveen23-Jul-07 18:36

23-Jul-07 18:36

Hi all,

I am trying to draw a gradient rectangle using the below code. But the problem is am not getting the correct color in the bottom. As per the code the expected color is RGB(0,0,255). But now I am getting RGB(3,0,252). Is there any way to show the correct value?

Color clr1( 255,255,0,0 );<br />
Color clr2( 255,0,0,255 );<br />
Rect rect( 0,0,100,100 );<br />
LinearGradientBrush pushedFace( rect, clr1, clr2, LinearGradientModeVertical );<br />
CClientDC dc(this);<br />
Graphics gr(dc.m_hDC);<br />
gr.FillRectangle( &pushedFace,rect );

Thanks in advance

nave

[OpenedFileFinder]

Mark Salsbery23-Jul-07 19:11

23-Jul-07 19:11

Naveen.R wrote:
Is there any way to show the correct value?

Add 1 to the rect height.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Naveen23-Jul-07 19:14

23-Jul-07 19:14

you mean like

LinearGradientBrush pushedFace( Rect( 0,0, 30, 101 ), clr1, clr2, LinearGradientModeVertical );.

In this case the color became more lighter. RGB(5,0,250) Frown | :(

nave

[OpenedFileFinder]

Mark Salsbery23-Jul-07 19:20

23-Jul-07 19:20

You're right! LOL sorry.

The problem is with the math (apparently which I'm too tired to comprehend Smile | :)

).

Incrementing evenly through 100 rows from 0 to 255, the last row ends at 252.45 or 252.
There's no way around it that I know of except adjusting the width/height to a value that makes
it come out exact.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Naveen23-Jul-07 20:12

23-Jul-07 20:12

Mark Salsbery wrote:
Incrementing evenly through 100 rows from 0 to 255

Well I tried making the following changes. Set the height as 255.clr1 = RGB( 0,0,0), clr2 = RGB(0,0,255 )

In this case the color should come correct isnt it? but now the color is 0,0,254 at the bottom( I know the color change is not noticeable. But I have to meet the specifications... ).

nave

[OpenedFileFinder]

Mark Salsbery23-Jul-07 20:29

23-Jul-07 20:29

You may have to come up with your own formula.

If they use a formula similar to this one: Using color gradients as backgrounds in your
dialogs and views[^], then it will never be exact on the last row.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Naveen23-Jul-07 20:38