Problem with managed and unmanaged mixed coding - Managed C++/CLI Discussion Boards

John Schroedl21-Jul-11 4:30

21-Jul-11 4:30

The delete is not necessary as this is a references and the GC will collect that context object when there are no more outstanding references. The delete is probably just attempting to make it explicit and hope to clean up sooner from what I can tell.

Book for Managed Extenstion for Vc++

Vijjuuu.1-Jul-11 21:34

Vijjuuu.

1-Jul-11 21:34

Hi All,

Can any suggest me book that explains better for mangaged extenstions for VC++ for .Net Version 2.0 and above ?

Re: Book for Managed Extenstion for Vc++

Ger Hayden1-Jul-11 22:44

Ger Hayden

1-Jul-11 22:44

Try Pro Visual C++/CLI for .Net 3.5 by Stephen Fraser from Apress

Ger

Re: Book for Managed Extenstion for Vc++

Vijjuuu.3-Jul-11 7:22

Vijjuuu.

3-Jul-11 7:22

Thanks Ger Hayden.

Re: Book for Managed Extenstion for Vc++

Mark Salsbery3-Jul-11 7:50

Mark Salsbery

3-Jul-11 7:50

You do know that managed extensions has been deprecated for quite some time, and it's now C++/CLI, right?

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

Re: Book for Managed Extenstion for Vc++ [modified]

ian__lindsay4-Jul-11 5:34

ian__lindsay

4-Jul-11 5:34

You can do a lot worse than Nish's book, C++/CLI in action (see http://www.manning.com/sivakumar/[^] ). I found it a really good introduction to one of the better things to come out of Microsoft in recent years, C++/CLI. Highly recommended.

modified on Tuesday, July 5, 2011 4:33 AM

Re: Book for Managed Extenstion for Vc++

Vijjuuu.4-Jul-11 21:08

Vijjuuu.

4-Jul-11 21:08

Thanks Lindsay.

Problem with managed and unmanaged mixed coding

Lighter Joul1-Jul-11 13:56

Lighter Joul

1-Jul-11 13:56

This maybe a common question, and maybe there are many articles and threads talking about the mixed coding.

But all the mixed coding seems prefer to using #pragram unmanaged/managed, and using dll import, something like this. I plan to make a winform program, and when I press some button, the program can call the unmanged function. So in that case, I should call the unamaged function in button click event, like this:

private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
// call the unmanaged function
CallUnmanaged();
}

However, I had compile error: 'CallUnmanaged': identifier not found. I tried to use extern the unmanged function in the managed codes, there are still many errors.

Anyone can tell me how to fix this without using dll import? just simpile function call. Thanks.

Best wishes

Joul

Re: Problem with managed and unmanaged mixed coding

Philippe Mori1-Jul-11 15:45

Philippe Mori

1-Jul-11 15:45

You must tell the compiler where to find the function typically by adding the appropriate include directive... or you somehow have to declare the function somewhere.

Is CallUnmanaged in another DLL? Is so, you have to properly export/import the function. If the function is in the same DLL then a simple declaration will do.

Typically function are declared in header files and header files then be included to use that function. If the function is uses across DLL, then it must be exported/imported as otherwise it would be visible from outside the original DLL.

Importing manged code is easier as we only have to add a reference to the DLL. For unmanaged function though, they mus be made visible to the compiler before being used by either including the file with the declaration or duplicating the declaration (normally not recommanded).

Philippe Mori

Re: Problem with managed and unmanaged mixed coding

Lighter Joul2-Jul-11 1:33

Lighter Joul

2-Jul-11 1:33

Thanks Mori, the CallUnmanaged function is defined by another .cpp native file of the project solution. That's I just want to call the CallUnmanaged function without through DLL. The compiler doesn't know the native function, that's the key problem. Maybe this is a simple question. Smile | :)

Joul

Re: Problem with managed and unmanaged mixed coding

Philippe Mori2-Jul-11 1:55

Philippe Mori

2-Jul-11 1:55

Well, generally all functions in a .cpp that are intended to be used from other files in the project should also be declared in the corresponding header. Then in the file where you want to call the unmanaged function, you just include that file.

In fact, this is the same for managed functions inside the project or any functions in standard librairies.

For this aspect C+/CLI works exactly as C++. The main difference with standard C++ is that when you add a reference to a managed DLL, all public symbols will be visible without any additionnal include to all file in that project. So for managed code outside the current project, C++/CLI behave more like C#.

ProjectA
unmanaged.h

// Since the functionm is intended to be used by multiple file,
// it should be declared inside an header file.
void UnmanagedFunction();

unmanaged.cpp

#include "unmanaged.h"

void UnmanagedFunction()
{
   // Do something
}

other.cpp

#include "unmanaged.h"
void CallingFunction()
{
  // The following function will be defined since it is declared 
  // inside unmanaged.h which is include by this file.
  // By the way, if the function was inside a different namespace, 
  // you will have to qualify the call or explicitly uses that 
  // namespace (not much different that regular C++)
  UnmanagedFunction();
}

Philippe Mori

Re: Problem with managed and unmanaged mixed coding

Lighter Joul2-Jul-11 3:35

Lighter Joul

2-Jul-11 3:35

Hi Mori,

Thanks for your kind help, I got your meanings and solved the problem. Many thanks Smile | :)

Joul

EDIT CONTROL password style

RomTibi30-Jun-11 7:04

RomTibi

30-Jun-11 7:04

I build an app w/VC++6. I design a window with an EDIT CONTROL (IDD_MYEDIT), associate a CEdit control (m_myedit). I switched on the PASSWORD style of the control.
Can be triggered this style on or off during the program running? Confused | :confused:

36. When you surround an army, leave an outlet free.
...
Do not press a desperate foe too hard.

SUN-TZU - Art of War

Re: EDIT CONTROL password style

Mark Salsbery30-Jun-11 8:20

Mark Salsbery

30-Jun-11 8:20

After the edit control has been created, the ES_PASSWORD style can't be changed.

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

Debugging an application minidump using windbg

Prasann Mayekar9-Jun-11 23:01

Prasann Mayekar

9-Jun-11 23:01

i have an c++ application build with /clr option and have integrated crash reporting feature.
the crash dump it generates does not show line numbers when i debug the dump using windbg.
(i found that applications build with clr does not show line numbers)

it shows the function name where it crashed but not the exact line number. for eg

it shows:
03434456 02312434 CExApp::OnOpenFile() + 0x30c

Is there any way to calculate the line number by using the offset 0x30c ?

thanks

cross-post alert

Luc Pattyn10-Jun-11 1:08

Luc Pattyn

10-Jun-11 1:08

Luc Pattyn [My Articles] Nil Volentibus Arduum

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Multi-Project Solution in visual studio 2008 (C++/CLI) (Windows Form Application).

PrajaktPatil6-Jun-11 1:24

PrajaktPatil

6-Jun-11 1:24

I am beginner in visual studio 2008 (C++/CLI) (Windows Form Application).
Can anyone help me Please..?
I want to know that how we can create multi-project solution in following way?
for example..
I have two projects "A" and "B".
can form of "B" called from "A"'s click event?
Thanks in advance.

Re: Multi-Project Solution in visual studio 2008 (C++/CLI) (Windows Form Application).

Mark Salsbery6-Jun-11 7:04

Mark Salsbery

6-Jun-11 7:04

If the two projects create executables, then you'll need some form of Interprocess Communication[^] for the two processes to communicate.

Or is one or more of the projects a library?

What are you trying to do?

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

Re: Multi-Project Solution in visual studio 2008 (C++/CLI) (Windows Form Application).

PrajaktPatil6-Jun-11 23:20

PrajaktPatil

6-Jun-11 23:20

Thanks for your quick reply

I am studying the Interprocess Communication link that you suggested to me.

Neither the projects are any type of library

The scenario is as:
Our company have too many (more than 20 in numbers) products (Hardware units) needs separate UI to handle Inputs and Outputs.

1. It is difficult to handle different software application for each product.

2. If customer has more than one products of our company then he should be able to select dynamically which application will run.

so I am trying to integrate all the needed and related applications in one solution.

Re: Multi-Project Solution in visual studio 2008 (C++/CLI) (Windows Form Application).

Albert Holguin8-Jun-11 18:48

Albert Holguin

8-Jun-11 18:48

If you just have a main solution (creating an executable) and all you're trying to do is spawn other applications when a users selects something within the main app, then its easy, all you have to do is know how to start the secondary application.

Re: Multi-Project Solution in visual studio 2008 (C++/CLI) (Windows Form Application).

Philippe Mori2-Jul-11 2:17

Philippe Mori

2-Jul-11 2:17

If projects are managed DLL, then you could do anything you want. The only thing to be aware is that reference to others DLL are unidirectionnal.

Assuming that each project are independant of the other, you could then have:
- ProjectA.dll (managed DLL with forms for A)
- ProjectB.dll (managed DLL with forms for B)
- ProjectC.dll (managed DLL with forms for C)
- MainApplication.exe (main application with reference to other DLLs)

MainApplication will then be able to uses any public forms in other DLLs. It will be able to uses events generated by those forms.

You may also need to add an extra DLL that will be referenced by each project if you need some common functionality.

By the way, then main application I have developped has many C++/CLI and many C# DLL.

I prefer to uses C# for the UI as design-time support is far superior. The main problem with that is that when refactoring code, sometimes, I have to convert some C++/CLI code to C# and vice-versa. I was using .NET Reflector with C++/CLI plug-in but now the new version is a paid product and old plug-in does not seems to be supported.

Philippe Mori

Access methods from .Net C# COM object from Unmanaged C++ code

Member 79736701-Jun-11 23:20

Member 7973670

1-Jun-11 23:20

I have prepeared project folllowing instrctions given in this article(Calling Managed .NET C# COM Objects from Unmanaged C++ Code).
I have used VS 2008 and .Net Framework 2.0 for both projects.

I am able to access ShowDialog() method as shown in this article but when i added another method to same interface it was not available in c++.

I checked both .tlb and .tlh file I can see both of them having declaration of new method added.
but I try to acces it through pDotNetCOMPtr-><new method="" not="" included="">

Please let me know what I am missing?

Re: Access methods from .Net C# COM object from Unmanaged C++ code

MicroVirus18-Jun-11 3:49

MicroVirus

18-Jun-11 3:49

Did you rebuild the .NET project?

Also, it helps if you could show the code.

Re: Access methods from .Net C# COM object from Unmanaged C++ code

Philippe Mori2-Jul-11 2:30

Philippe Mori

2-Jul-11 2:30

By the way, you might also consider making a mixed-mode C++ code. If you cannot put your original C++ code in that project without problems, you might then explore the possibility to create a mixed-mode layer.

In my case, my C++ code is compiled in mixed mode (/clr) so I can mix regular C++ with managed C++ in the same DLL. It might not always be feasible in existing code is large and uses incompatible options.

In that latter case, I might also try to have an extra DLL (mixed-mode C++) that would make the bridge between unmanaged C++ and managed code. Then existing C++ code would uses that DLL to indirectly call C# code.

This approch have some advantage like you could somehow adapt C++ code to be easier to uses or follows your C++ code convention or do some transformation between types like converting System::String^ to wstring for uses in C++.

I have never really tried the C# COM objects by their should be no problem with that method provided that all required symbols are public and GUID are assigned when required.

Philippe Mori

Question about Connecting to Postgresql with ODBC

Lighter Joul27-May-11 5:07

Lighter Joul

27-May-11 5:07

Hi all,

I wanna to connect postgresql, and I prefer to ODBC with MFC before.

However, I don't know how to do this by c++/cli, can any kind man give me some advice or some online ariticle about this?

Thanks in advance.

Joul

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