I created a COM C++ and register it in the Windows system.
Now, If I'm creatine a C++ application and would like to load it and call the function objects, I'm using the CoCreateInstance function.
What should I do instead that if I want to create .NET (C#) application and load the COM C++?
Thanks
Assuming you are using Visual Studio:
Right click on your project, then select "Add Reference". In the following dialog, just select the Tab "COM". There you can select your COM library, Visual Studio will take care of creating an Interop assembly and you can start using your library from C#.
Related
We have a collection of C# functions (in a DLL) that are to be passed over COM, to be easily access from Visual Studio via the "Add Reference" feature. I've setup the registry such that it indeed shows it under Extensions when clicking Add Reference on a Visual Studio C# project.
However, the C# COM DLL calls on a C++ DLL. When I create a test C# project and then click "Add Reference" to add my C# COM DLL, it succeeds in adding the class, but does not include the C++ DLL, thus causing it to fail in the build process.
Manually adding the C++ DLL into the output causes it to function properly, but it would be nice to be able to click "Add Reference" and all of the necessary files are built into the output.
I followed the instructions here, creating the proper entry in the registry to the folder where both the C++ DLL and the C# DLL are located, but it doesn't seem to include it when simply clicking "Add Reference."
How would I go about getting my desired results? Note that the C++ DLL does not use any COM interface, it is just a standard DLL that exports functions and the C# COM DLL uses DllImport to access them.
I'm a C# programmer who hasn't used C++ since the pre-.Net days.
I have a C# .Net DLL that I use with other C# programs. In the calling program in Visual Studio I simply do an "Add Resource..." and a Using" statement in the code that calls into it and voilà! there it is.
Now I have a customer who wants to access our DLL in a Visual Studio 2010 C++ (CLI) program. So I want to make a practice C++ program that uses our DLL. What's the equivalent of Add Reference in a C++/CLI project and what do I put in the program to expose the namespace for my DLL? Where does the DLL have to physically be? In the Solution Explorer in Visual Studio for the C++ project I don't see the same things as I do in a C# project.
Right click on the project in Visual Studio, and select "References". You should have a dialog with a few references already attached ("System" and a few others perhaps). Click "Add New Reference" and browse to the assembly (or project if it's in the same solution) that you want to use.
Have you read the knowledgebase on calling native (.net) code from c++? It is about Visual Studio 2005, but the process should be the same.
How to call a managed DLL from native Visual C++ code in Visual Studio.NET or in Visual Studio
And there is a related (identical) question on here as well:
using c# dll in project c++
Edit since I missed the bit where it's about a managed C++ project:
How to add references to a managed Visual C++ project
.NET references
.NET references point to shared assemblies. For example, the assembly System.Windows.Forms.dll is a standard assembly for accessing the Windows Forms classes. In order to use this assembly in a Managed C++ application, you simply have to reference it with a #using preprocessor directive, as shown here:
#using <System.Windows.Forms.dll>
I have been trying to monitor video memory for a highly performance intensive program.
So I used the NVIDIA CUDA libraries in a C++ Visual Studio Application to collect the data I need.
Unfortunately I need a package that can be used with Ruby, C# and the Software Testing tools my company has.
So I decided to compile a C++ DLL and import it into a C# Visual Studio Project for testing.
I was able to compile the DLL but importing it into my Visual C# Program has been an issue.
I right Click on References -> Add Reference. Then I click on the Browse tab and browse to the location of my DLL; "TestProgram.dll" and I click "OK"
Then I get the following Error message "A reference to C:.... could not be added. Please make sure that the file is accessible, and that it is a valid assembly or COM component."
What I have tried so far:
1. Importing the DLL from several different locations on my system.
2. Moving the DLL into my Solution Explorer and importing it
3. Using the "Invoke" method: [DllImport("PathToMyDll")]
4. Using the "Invoke" method with just my dll name.
5. Typing 'using' path to my DLL
6. Exporting the dll as a .lib file instead
What am I doing wrong? I thought that if I exported a DLL using Visual Studio 2010 then surely that same DLL could be Added into a Visual Studio 2010 project.
Well, is it a valid Assembly or COM component? Just because it's a C++ DLL doesn't mean it can be used with just a reference, in fact, most can't. It needs to be a managed DLL or a COM object. If it's none of those, then you have to invoke unmanaged code from a managed assembly. That means defining each function in a stub.
More info here: how to call a C++ dll exported function from c#
Be aware, you also have to deal with 64/32 bit issues, since if the DLL is compiled for 32 bit, you can't use it in a 64 bit application.
I found the solution to this problem. CUDA creates a Windows Console Application project. So the solution was to just use that instead of a DLL.
This worked well because Ruby, Test Complete and Visual C# can read the output from a basic .exe console program (with some work).
The compiled exe is simple. All I need to do is pass in an integer as an argument when I launch the program and the program will get the data I need from my NVIDIA card.
The challenge now will be finding a good way to interface with the .exe.
I have a C# class library which I also use via COM Interop. To test the library I added a C# test app to the solution, set it to the startup project and I can test it that way. The library works fine this way but one function is not working when called via COM Interop from a Visual C++ 6 test application. How do I debug the library in this situation? I searched for a solution on Google but the only advice I can find is to add a test app to the solution which of course I can't do in this situation.
EDIT: Very sorry. I forgot to say the Visual C++ test application is Visual C++ 6.
First, open boot Visual Studio and Visual C++. Start your test application in VC++. After that, in VS, open the Debug menu and choose the Attach to process. This will show you a list of current process that are running, choose the one corresponding to your test application and click on Attach. This will enabled you to put breakpoint and debug your DLL.
I created a C# dll using Visual Studio 2010.
I'm able to register it using regasm. I also used [ComVisible(true)] for my class.
The issue is, I'm not able to access this dll from VBScript.
I remeber there was a setting in the Project | Properties screen.
What is that setting? Or is there another way?
see this excellent post on creating COM components using Visual C#.NET
http://blog.stevedoria.net/20051008/creating-com-components-using-visual-csharp-dot-net