I have a source file written in C++, performing some simulation. I would like to create a user interface for this in C#. How can I have both C++ and C# in a single Visual Studio solution?
What I did so far was I created a .NET C# project and solution, and then a native project as a DLL library. I have marked the C# project as "Depends on" the C++ dll. I have provided the necessary dllexport directives and imported using DllImport. Everything compiles fine, but when I execute the application, the dll is not found:
Unable to load DLL 'xxxx.dll': The specified module could not be found.
It is no surprise the DLL is not found, as the application is run from its output directory and the output directories are different for the C# and C++ projects. I do not want to write an explicit path as my import like `"..\..\Debug\xxxxx.dll".
Is there some common way how to structure a solution containing native a Dll and C# app so that the C# app can call the native Dll?
If you know that after deployment your C++ DLL will be in the same folder as your C# DLL (or executable), then on simple way to solve the problem is to use the PostBuild event (Project properties, Build events).
You can add a copy command that will put your C++ DLL into the C# output folder.
I found a very comfortable way, which might have some unexpected drawbacks, but I do not see any so far: I can enable CLR for the C++ DLL project, making it "mixed", even if it in fact does not contain any managed code, and then the project building it can be made a Reference in the C# .NET project.
To make the project mixed mode set Configuration Properties / General / Common Language Runtime Support to Common Language Runtime Support (/clr).
After this the build system copies the DLL into the application output folder automatically.
Related
I have a solution with a managed C++ project and a C# project. The C# project is a class library project containing the GUI classes I use from the C++ project. This works well, but building results in two DLLs.
Is there a way of using the C# objects from the C++ project without having a dynamically linked library generated by the C# project (is there a way to embed the C# types into the managed C++ project)?
I am using Visual Studio 2015.
There is a way, but it is far outside the tooling you are using to be able to accomplish it.
You can use command line tooling to create a multi netmodule assembly.
Managed assemblies are built of one or more "netmodules". Typically in a C# project, there is only one netmodule, and the C# compiler builds it and then links it into the assembly it produces. By using the command line tools, you can build only a module, then link it with the C++ module into an assembly.
i have received a wrapper class for a C++ unmanaged code, which i need to add to my web project and call through c#.
1) in a c# desktop application project
When i'm adding references i can only add the wrapper dll. cannot add the unmanaged dll. i think this is not a issue. Then when i'm buliding and running it gives an error saying
Could not load file or assembly 'AskCmnWrapper.DLL' or one of its dependencies. The specified module could not be found.
So then i manually copied my unmanaged dll to the bin folder . It worked fine
2) in a c# web application
i got the same above issue. manually copied my unmanaged dll to the bin folder when i'm trying to run it with iis express (through vs2012) . but it's not working. Is there any special configurations to be made when running unmanaged dll/wrappers in web applications?
please guide me.
thank you.
Chances are you are missing some of the required C++ redistributables or other dependencies. Run Dependendy Walker on your native DLL to see which ones are are missing.
Ideally, you want to make a C++/CLI project which contains the source code of the native library you are wrapping, and write a managed C++/CLI wrapper on top of it, in the same project. This way only the "wrapper" (containing the native code) will be required in your folder.
If you don't have the source, and you can not statically link the library into your C++/CLI project, you will need to have both the wrapper DLL and the native DLL in the directory at run time, as that's when they will be linked.
I'm trying to make c# bindings for a library. I used cmake to create a visual studio 2010 solution from the library source, and that compiled fine. I used the included .i file to create the wrappers as per the instructions here (https://code.google.com/p/labstreaminglayer/source/browse/LSL/liblsl-Generic/AUTOGENERATE%20HOWTO.txt ) using cygwin. I then added the resulting liblsl_warp.cxx file to the same project. It still compiled fine, so I would assume that the resulting .dll includes the required bindings.
I've added that project to my c# application and am trying to add a reference from the c# project to the resulting dll (also tried adding a reference to the project). The only error I get is A reference to 'lsl' could not be added..
What steps am I missing? I looked at a couple examples, and I am basically setup the same way, but their examples are significantly easier.
SWIG produces both C# and C++ source code. The C# code uses DllImport to import the functions from the C++ side - it doesn't use .net-like bindings. Therefore the C++ DLL does not need to be (and cannot be) registered, and hence can't be 'referenced'. Referencing is for registered DLLs.
So you have a C++ DLL and a C# exe. Just ensure the C++ DLL can be found by the exe, by putting it in the same folder for example. Don't worry about referencing it.
Sorry if this is an obvious question, but I'm new to C# and am trying to use 2 dll's for a project. Where do I put them?
I tried to add SoundTouch.dll as a reference in an empty C# project, but Visual Studio said to make sure that the file is accessible and that it is a valid assembly or COM component. I was suggested to put the dll's into the \bin\debug path, but where is that? Thanks for your help.
Each project should have it's own \bin\debug (and \bin\release) directory structure under it's project directory, but they will not be created until you Build the project. As for the invalid assembly, it sounds like your dll has either become corrupted or is not a valid .NET assembly.
Edit: Looking at the SoundTouch website, someone has already created a wrapper for this dll suitable for use with C# and it can be found here
If your DLL is a .NET or COM DLL, you can simply add a reference in Visual Studio. For details on that procedure see
http://msdn.microsoft.com/en-us/library/wkze6zky(v=vs.110).aspx
If the DLL is a Win32 DLL (does not expose a COM interface) you can interface with it via the Platform Invoke (P/Invoke) mechanism.
http://msdn.microsoft.com/en-us/library/aa288468(v=vs.71).aspx
When using P/Invoke the DLL must reside in a location that can be resolved by the .NET runtime, and you use the DllImport attribute to "pull" entry points from the DLL into your C# code, e.g.
[DllImport("msvcrt.dll", EntryPoint="puts")]
.NET will search for the Win32 DLL in the same directory where the .exe is located. If you build under Visual Studio, a folder will be created under your project folder
bin\debug
for a debug build, or for a release build
bin\release
Premise:
Wrote a COM-callable wrapper (CCW) written in C# to be called by VB6 code.
The C# code has .NET libraries (third party) that it must utilize.
The wrapped C# class instantiates fine, raises events properly, takes method calls properly.
Problem:
The VB6 code, when running the C# code, gets an error when the C# code attempts to access the additional .NET libraries mentioned above.
Process tested:
C# wrapped code completed.
VB6 code written, references the COM dll created.
"File not found..." error received when the C# code tries to access the .NET libraries from inside itself.
Copied the third party .NET libraries into the main folder of the VB6 code (also into system32 folder).
Still "File not found..." error.
Wrote a C# Windows Form test project. Referenced the C# wrapped code.
Received the same error as the VB6 code.
In C# Windows Form test project, referenced the .NET libraries used by the C# wrapped code.
The program ran just fine.
Conclusion/Question:
Can VB6 call/use a com-callable wrapped C# program that references other third party .NET libraries?
I've done this with tons of third party libraries and as long as the third party library DLL's are in the same directory as your C# DLL's there shouldn't be a problem.
Copying them into the same directory as your VB6 code will do nothing, the effective directory of VB6 code when running the in VB6 debugger is %ProgramFiles%\Microsoft Visual Studio\VB98, so the code running will have no visibility of that.
The system32 directory has nothing to do with DotNet dll's (the only DLL's they would affect is PInvoke'd dll's and you say you add a reference so that isn't the case).
Adding the third party library to the GAC should fix things, however that is not necessarily possible/easy due to the need to sign the DLL. So just make sure the Libraries you are referencing are in the directory of YOUR library and that VB6 is actually referencing that version of your library (Debug/Release whatever what last compiled). You may want to hand RegAsm the library to make sure the correct library is Com Registered.
So to sumerize, suppose your source code looks like this:
c:\projects\vb6project
c:\projects\c#project
And your project is set to Debug, the third party libraries should be in:
c:\projects\c#project\bin\Debug
When you actually want to distribute the application, make sure that ALL the libraries are in the same directory as your VB6 exe.
This will mirror somewhat the answer by Kris Erickson.
First, for my usage which solves these problems, I did not use the GAC. Assuming that my VB6 application is in c:\program files\mycompany\vb6app.exe, I placed the COM-friendly .NET dll (lets call it net4vb.dll) in the folder with the executable. I then regsiter that dll there with RegAsm using the /codebase option. Finally, I place the .NET assembly that I'm wrapping or using (lets call it purenet.dll) in that folder as well.
At this point, vb6app.exe should run with no errors.
It is important to note that if you select the "Register for COM Interop" in Visual Studio then it will overwrite the registration you did above. So do not use this option. Stick with the command-line tools only for this.