Is it possible to step into the COM C++ code that is being used through a .net interop layer created by tlbimp.exe from a C++ program. I see that the symbols for the COM C++ dll is loaded in the Debug->Modules window.
It is possible, but you'll need to set your Visual Studio debugger to mixed mode in project properties. This is located under Project properties->Configuration Properties->Debugging->Debugger Type
Related
I am using Visual Studio 2015 Community Edition and I followed Microsoft's tutorial on creating implicit dll's here https://msdn.microsoft.com/en-us/library/ms235636.aspx and I referenced the dll successfully in a C++ console application (I did it just to see if it would work).
When I tried adding the dll project to the references for a Visual Basic Windows Form Application, I got an error saying "A reference to 'DLL Project Name' could not be added." After some research, I think it's because VB targets the .NET framework while the C++ dll targets Windows, but that's all I managed to figure out. I would greatly appreciate any help on reconciling this, or setting up some solution that involves a C++ dll and a GUI project that uses the dll (I just chose VB for the GUI since it's really quick and easy to set up).
Note that both the DLL project and the Visual Basic project are in the same solution.
Your tutorial won't help you invoke the code from .NET and you are correct in assuming it to be a .NET framework inter-op. issue. You can use p-invoke to import and call the DLL or create a COM wrapper around your DLL and register it in the GAC then reference it via a COM CreateObject call.
Other possibilities are to convert it to a C++/CLI .NET C++ DLL.
References:
P-Invoke
COM
-UPDATE-
I suppose I should also mention that if you target Universal Windows Platform (UWP), it also provides a clean binding across .NET and C++ and hides some of the busy COM wire-up.
A C++ DLL should be added to your *.NET application with a post-build event "xcopy" command like this one:
xcopy "$(SolutionDir)DLL\$(ConfigurationName)"\*.dll "$(TargetDir)"*.* /Y
from your selected project go to Project-->Properties-->Compile-->Build Events-->Post-build event command line
Enter the appropriate copy command.
In the above example, several C++ DLLs were collected in a "DLL" folder in the Solutions Directory. They all get copied to the application folder every time the application is built. There were DEBUG and RELEASE versions of those DLLs in separate sub-folders.
As other posters noted, you also must have correct p-invoke declarations for your C++ DLLs in your *.NET code.
Ever since I added Common Language Runtime Support (/clr) for my project I
have been having so much trouble getting information from the code I am
debugging in C++. I had to enable this support so that I could load a
.NET *dll in the C++ code for my project. I am not sure why this is
happening, but I need to be able to indentify what is causing this.
The way I debug is that I attach to a java process that loads my C++ code which
is in a dll. A *pdb file for that *dll is in the same directory where the *dll is
loaded from.
I keep getting this 'undefined value' for various primitive types I could easilly
view before. Is there some easy tutorial on how to get debugging information correctly
loaded onto visual studio 2010.
Background: Vendor has provided me ActiveX Dll, no header files or .tlb file or anything such.
I am using Visual Stdio 2010 and using win32 C++.
The problem I am facing is how to load or reference dll?
I cannot reference the dll through solution explorer because it is unmanaged project.
When I try to use #import, it give me compile error saying XXX.tlb file not found. But I don't have .tlb type file.
The other option I tried was to open the dll with OLE viewer and copy the dll definitions and then paste in .idl extension file I created with Visual Studio. Then I executed midl on the idl file to create .h file but that did not help either. When I try use the classes, its gives me "abstract classes cannot be used or referenced" error.
There are other questions asked on the matter but not straight forward and the answers are not marked as answered or upvoted.
I want to know what are the different methods available to load the ActiveX dll in win32 C++ project in visual studio 2010 and which one should be preferred when? If there is a thread that actually addresses my issue please point me to that.
Thanks
If you are able to see the interface definitions using OLE View it means that the type library is embedded into the dll resources. So if you use #import "YourActiveX.dll" it should work.
You need
Register the COM (Active X) component in windows using regsvr32 : regsvr32 my_dll.dll
Then use COM to interact with the component. This is a good tutorial.
As far as I can tell, Visual Studio 2008 provides two ways of making a MFC DLL:
New Project -> MFC DLL
New Project -> Win32 Project -> select DLL, Export symbols, & MFC
What is the difference? The two methods seem to generate very different starter code. The second methods appears to generate code that I would expect to see for a DLL. Thanks.
The first creates what is called an MFC "Extension DLL". The key distinction here is that this DLL is only available to MFC programs and other DLLs that use MFC. Its public interface may pass MFC types between the DLL and its clients.
The second creates a "Regular DLL" that links to MFC. It can use MFC internally but exposes an MFC-independent interface so non-MFC programs can use it too.
There are more distinctions, which you can read about in the linked pages.
I have a vb project which calls functions in a dll.
The dll is created in a separate vs project (portaudio), which is written in c.
The dll c project compiles clean and builds the required dll, which I am currently dropping in c:\windows\system to vb runtime can see it.
VB Project lives in c:\devprojects\vbtest
C Project lives in c:\devprojects\portaudio with the project file in c:\devprojects\portaudio\build\msvc. Dll created in Win32\debug under this msvc directory.
When I call the dll function, is it possible for the vs debugger to step through the c function in the dll - I have all the code etc, but I don't know if VS2005 supports this kind of mixed language debugging.
If this is possible, could you advise how I should set up my Visual Studio to achieve this.
Many thanks
David
It is not necessary to have both projects in the same solution, but you should compile both projects with debug symbols enabled.
Now in your VB net solution Project/Properties, in the Debug tab make sure that "Enable unmanaged code debugging" is checked.
Also make sure that the dll loaded is in the same place where it was compiled, else it may not found the pdb where the debug symbols are stored.
Create a solution with both projects, add the reference in VB project to C project using 'Add Reference..' dialog -> Project and build them all in debug mode.
How do you calls C dll from VB?
If its VB.NET then this is very easy, just set up a solution with both projects under it, set up their dependencies and ensure that on build the debug version of the VB project links to the debug lib/dll produced from your C++ project. Visual Studio does the rest.
I've done this before a couple of times with C# applications calling a C++ dll. I didn't intend to set this up, but tried stepping through whilst debugging assuming I would get the assembly listing and could at least work out somethig of what was going wrong with my code... however it loaded the correct .cpp file and allowed me to continue stepping through that code.