Using C# dll in C++ code - c#

I need to integrate this C# dll
in my C++ code. I want to call some functions written in C# from dll and the rest of code write in C++. What is the easiest and quickest way to do it? The program will be executed only on Windows.

There are basically two cases to call a .NET DLL from unmanaged code:
The .NET DLL exposes a COM interface. In this case, you can use COM from your C++ code.
The .NET DLL does not expose a COM interface. In this case, you have two possibilities (to make it simple):
2.a. host the CLR as described here: Loading the Common Language Runtime into a Process
2.b. write a piece of managed C++ code (another DLL - written in C++/CLI) to wrap the .NET DLL and expose 'old way' DLL exports to unmanaged clients.
I don't specifically know the sharpbox system, but it looks like it's pure .NET and does not expose COM interfaces, so 2.b might be the best way to do it (not so easy...). Maybe it has a REST/Web easier API you could use.
PS: you can also add exports to a .NET DLL. This is described here: Is is possible to export functions from a C# DLL like in VS C++? but it's kinda hacky.

Related

Use of cross-platform C++ dynamic library from C# Uno project

I'm working on the port of the C# UWP project to Uno-Platform. The original project references a lot of logic from C++ DLLs. The interface between C# and C++ library is rather big to write PInvoke wrappers manually.
Is there any complete solution to automate the calling of C++ library methods from .NET?
The Uno Platform does not provide anything specific for this type of scenarios, and relies on what .NET already provides (P/Invoke in this case).
You may want to take a look at https://github.com/EgorBo/CppPinvokeGenerator or https://github.com/xoofx/CppAst.NET to generate C# from the C++ code.

How can I call a C# DLL in C++? [duplicate]

I have a native C++ DLL, and I want to import a C# DLL and use some of its functions (for example connecting to a database).
Now I have read that you can turn the DLL into a TLB COM file, and I have done that no problems. My problem lies with the C++. To call that TLB file I need to set CLR support. I use themida to help secure all my DLL's as well as PEC. They do not support .net DLL's and when I enable CLR the programs recognize it as a .net DLL.
Is there anyway to call a c# function inside a .net DLL from inside a native C++ DLL without enabling CLR?
The best way in my opinion is to crate a C++/CLI lib that you can use to communicate between the layers.
This 3rd party library will be compiled with /clr enabled.
Then you can use the header definitions to the proper c++ function wrappers to call the C# functions.
C++/CLI can help you manage the call just the way you want it, and let you design the type casts the way you want them.

What is the right pattern for accessing a C# DLL from C++?

I generally work on Android/Java, but right now I'm working on Windows Phone 8.1. I have C++ code in a library that needs to be able to access the functionality in a provided C# Assembly DLL.
The C# DLL has an interfaces that needs to be implemented to receive callbacks from the DLL.
What I've tried:
I tried using a Windows Runtime Component to wrap around the DLL , but then it complains that the interface isn't valid to use with Windows Runtime Components.
I can wrap the DLL in a pile of C# code, and provide an interface in that to forward on any callbacks from the DLL to any implementation (C++), but the C++ code doesn't want to recognize the namespace as an existing namespace.
What is the missing piece?
I was able to access the DLL using a C# Windows Runtime Component. The callback interfaces from the DLL were implemented in C# and would call back into the C# Windows Runtime Component to do work.
The work to be done was calling a C++ Windows Runtime Component that would do the talking to the C# Windows Runtime Component. The C++ Windows Runtime Component could then be the gateway to the C++ library of code we have.
The C++/C# interoperability can be achieved in two ways: through Win32 DLLs or through COM components.
If you plan to use the Win32 approach you're gonna have to provide all the metadata in terms of CLR types, then the managed compiler will compile the metadata into the assembly and the JIT compiler will build stubs that performs the C#/Win32 conversion.
If you plan to use the COM components you'll have to use the Runtime Callable Wrappers, that will take care of instantiation, type navigation, error handling and memory management.
More information about RCW is here: http://msdn.microsoft.com/en-us/library/8bwh56xe(v=vs.110).aspx

How can I make a Win32 DLL that is reference-able in a C# application?

I have a rather large legacy nmake (Win32) project that creates a static library from native C++ code. I need to use this library in a C#/.Net application. In the past after much effort I had been successful at wrapping the static library in a managed C++ library, which I am then able to reference in a C#/.Net application. However, after receiving updates from the developers of the nmake project, and having gone through an many upgrades on my own build machine in the meantime, it is no longer working.
I am however able to import the cpp and header files of the nmake project and build it to a Win32 static library in VS 2010, by setting all of the preprocessor constants in the build properties. I set the build configuration type to DLL, and then try to add a reference to the Win32 output in my C#/.Net application hoping to use P/Invoke down the road, and it fails with a message "A reference to MyLibrary could not be added."
Is there a way to build the Win32 library so that it can be referenced by the C#/.Net project and so that I can use P/Invoke?
Is there a way to build the Win32 library so that it can be referenced by the C#/.Net project and so that I can use P/Invoke?
If you want to directly reference the library, you'll need to build a C++/CLI project using your library, and make managed wrappers.
If you want to use P/Invoke (which is a separate concept), you can make exports with a C API, and call those directly via P/Invoke.
The two approaches are both valid, but completely different in terms of implementation (C++/CLI vs. C API wrappers) on the native side, as well as used differently (directly referenced for C++/CLI vs. P/Invoke via [DllImport]).
You can use SWIG to generate wrappers for your code. SWIG is a very powerful tool and worth taking the time learn. It creates wrappers for a number of languages including Python, C#, and Java so if you get it working with one language it is fairly easy to use in other languages as well. It will generate all the wrapper code for you, although you will probably need to do some work with type. You use swig to create a special DLL that SWIG generates code for and then used supplied C# code to access the DLL without needing to deal with managed C++ assemblies which can be a nightmare to deal with.
http://www.swig.org/Doc2.0/SWIGDocumentation.html
Edit: my explanation may not be that clear and the docs are pretty overwhelming, take a look at the "What is swig?" section here to get started:
http://www.swig.org/Doc2.0/SWIGDocumentation.html#Introduction_nn2

How to create native DLL in Visual Studio from C# code?

I have the source code of a C# program. I want to create a DLL out of it which I want to use in C++.
Is it possible to create a native DLL in Visual Studio 2008 which can be used in C++?
native <-> .Net interop is one of my pet disciplines, which is why I needed this as straightforward and reliable as possible.
The result was that I made me an MSBuild task which I just need to drag into a project to allow me to export static methods from pretty much any .Net language. And since the whole marshalling infrastructure works for exports as well, you can do pretty much anything with it that you want (like passing native/managed objects as IUnknown).
The resulting assembly will look to the consuming process like a real DLL, which means you can't have it to scale up to 64bit automatically anymore.
However, since you do have native bits in your application, you already have this issue anyways. ;-)
When you do not specifiy the CPU target in your C# project, my task will emit a warning that it created a folder for all targets (x86,x64 and Itanium), and there you'll have *.dll and *.pdb for each platform.
If you want the program to be native, and not managed, you'll need to port it to C++, instead of using C#.
That being said, you can compile it in C# into a library, and use it from C++ by using C++/CLI. This just requires that you compile the files that use the C# library with the /clr flag. This provides C++ access to the .NET framework, and lets you use libraries made in C# directly from C++.
Alternatively, you can use .NET's COM interop to expose the C# class(es) as COM objects, and then use those from native C++.
It is possible in Visual Studio 2008, but you're not going to be able to write it using C#.
To create a native DLL, you'll have to write your code using one of the unmanaged C++ project types.
You can expose the DLL to COM. Have a look here for some examples.
yes you can.
you need to create second project.
the project must be unmanaged (like "visual c++"->class library).
the name of this procedure is "calling from unmanaged code to managed code".
good to read unmanaged to managed (codeproject)
you must be aware, that any computer that using your dll must have preinstalled DotNet and Visual C++ Redistributable Package

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