In my project I got a device which comes with C++ Sample codes. The codes are ok and the device is working as expected.
But I need it to talk with my C# interface because all other devices are currently using C# interface.
So I am planning to create a DLL Wrapper for the driver. I will create a C++ Library of my own (from source code with proper interface) and Call this C++ Library from C# using DLLImport (just call my interfaces there.).
I am pretty sure it can be done this way, but I have never created a C++ Library and used it from C# yet. So, can anyone refer me to some tutorial that goes with my problem?
I am using C++/C# int VS.NET 2008.
Regards,
Maksud
Have a look at
using a class defined in a c++ dll in c# code
Another useful tool you have at your disposal is C++ CLI.
You can use C++ CLI to create an intermediate library - one that exposes managed classes but runs unmanaged C++ code. You can actually mix managed and unmanaged C++ in the same DLL.
The unmanaged portion can accesses the unmanaged DLLs without having to use the PInvoke functions.
Your C# code can access the managed classes in this intermediate library.
Depending on the DLL and what you need to do you may not need to create a wrapper directly. You might be able to get away with P/Invoke for the functions. You will need to evaluate your specific needs and what is already available in the libraries/code provided.
For anyone who comes to this question and are looking for answers, you may want to try xInterop NGen++ , a C# wrapper generator for native C++ DLL, which has been just released to the public, the tool can generate C# wrapper for native C++ DLL automatically and instantly by using advanced P/Invoke technologies. Check out the current version and a free version will be out soon.
(I am the author of the tool)
Related
In VS C/C++ you could use extern "C" __declspec(dllexport) -function declaration-.
How do I accomplish this in a C# dll? Is there C# code equivalent to the above code?
Edit: More info
I am trying to create an add in for Notepad++ and I want to use C#, but the common way I've seen so far is to use legacy C++ code with the above call to export a few of the functions that Notepad++ expects to import and call. There is an example app using C#, but this still requires a loader DLL, which I assume from the comments/answers below is the only way for C#.
Unmanaged Exports =>
https://sites.google.com/site/robertgiesecke/Home/uploads/unmanagedexports
DLLExport => https://github.com/3F/DllExport
How does it work?
Create a new classlibrary or proceed with an existing one.
Then add the UnmanagedExports Nuget package.
This is pretty much all setup that is required.
Now you can write any kind of static method, decorate it with [DllExport] and use it from native code.
It works just like DllImport, so you can customize the marshalling of parameters/result with MarshalAsAttribute.
During compilation, my task will modify the IL to add the required exports...
I've seen people do this before, but it required ildasm, adding the MSIL .export directive, and then reassembling. A program named dll_tool can do these steps for you.
If you want to build a mixed-mode DLL with both native and managed exports, you should be using C++/CLI, which is specially designed for this purpose.
Yes, it is possible to export functions from a C# dll in much the same way that C++ does it! You need a little help from an add-in Unmanaged Exports (DllExport for .Net) that facilitates this process, or from a similar method such as Exporting functions in C#/VB.NET to native code.
Please see Code to Export C# DLL to Metatrader Build 600+ for a working example using Robert Giesecke's C# Project Template for Unmanaged Exports to export a C# dll to a legacy application (Metatrader) that has a great deal of similarity to C++.
Additionally, you might find Native and .NET Interopability interesting though it is mostly geared toward accessing native code from within .NET rather than the other way around.
No, you cannot do that in the same sense as you do in C and C++.
But you can create COM API to achieve that which then you can use in C and C++ code.
See these articles
C# Classes as COM Objects
Calling Managed .NET C# COM Objects from Unmanaged C++ Code
COM Interop Part 1: C# Client Tutorial
i'm exploring the idea of use .net as a scripting language for my program.
i found a lot of examples on internet that shows how to host .net and then, from c++ call functions from .net.
But i need to go on the other way too, from this code in c#, i need to be able to create/call c++'s objects from this c# script, so i need to expose functions/objects to control it from C#.
How can i do it?
Simple Example to show what i'm talking about
I call my c++ method "CreateGUI". It'll call .net code: "InitializeGUI", and this "InitializeGUI" need to check if an object (for example, the texture) is instantiated inside C++.
Can someone help me?
Thanks!
If you use managed C++, you can create a managed C++ component which can be called from your C# code. If you use unmanaged C++, you can either create a C++ COM component and use it through C# via RCW (Runtime Callable Wrapper) mechanism or you can create a C++ dll and call it from C# via PInvoke.
You might also investigate Mono, which is explicitly intended to be embedded and will run any compiled .NET assembly, meaning the full powers of C#, VB.NET, even F# will be available.
I have a native C++ DLL using DirectX, that I want to be able to use through C# to be able to create content creation tools.
Adding COM would require quite an effort it seems.
Can P/Invoke be used to maintain classes using polymorphism, or would it require me to wrap most of the code to facilitate use of P/Invoke?
It there a better solution is available? Or should I even consider writing the tools in C++ using Qt perhaps?
I always feel that C++/CLI is always the best option when doing C# to C++ interop. You can easily create thin wrappers for an unmanaged library that will look exactly like a managed library to your C# code. It also gives you more control over how marshaling and pinning is performed.
There are ways to automatically generate C++/CLI I believe, but I've never used them.
More info on C++/CLI here:
http://msdn.microsoft.com/en-us/magazine/cc163681.aspx
I presume rendering with D3D directly from C# isn't an option? (because that certainly would be easier!)
A long time ago, I used SWIG to automatically maintain C# "bindings" of my C++ rendering DLL code. It uses P/Invoke to expose the C++ objects on the C# side, and you won't have to maintain that code anymore.
You don't need to write wrap on QT.
I advice you to write Observer class both in C# & C++, and hide calls of Native functions to it.
Schema is like this
Your code in C# -> Observer(C#) -> Native call to Observer(C++) -> Calls to your dll.
Is there a way to create C# objects and call methods from unmanaged C++, but without using COM Iterop? I am looking for something like JNI (but for .Net), where you can manually create the VM, create objects, etc.
If you are using C++/CLI then you can interact directly with both the managed world and unmanaged code, so interop is trivial.
You can also host the CLR yourself, and whilst the hosting API is COM based, you can then create any managed object. The process isn't a difficult as it sounds as a few API calls encapsulate a lot of functionality. There is a lot of info online, for example the MSDN documentation on "Hosting the Common Language Runtime".
There is a somewhat "undocumented" way of exporting C style API from a .NET class / method.
This ultimately leads to a situation where a .NET dll has exported APIs that can be called from C/C++ or anything that can consume .DLLs for that matter.
If you are into "reading" (beh ;) you can get a book called: Inside Microsoft® .NET IL Assembler where you'll find this technique in chapter 15: "Managed Methods as Unmanaged Exports"
There's also a nice example project on code-project you can use as a starting point for 32-bit environments:
http://www.codeproject.com/KB/dotnet/DllExport.aspx
You can decide file-by-file in your C++ project whether or not to use managed C++. Try changing the settings a file in your project so that it compiles as managed. Put the calls there to your C# object.
There's a cost to crossing the C++/C# border, so you should analyse where to do it. Like, you wouldn't want to do it inside a loop.
I am author of jni4net, open source intraprocess bridge between JVM and CLR. It's build on top of JNI and PInvoke. No C/C++ code needed. I hope it will help you.
I have a C# class library that contains methods that need to be used with an external application. Unfortunately this external application only supports external APIs in C/C++.
Suppose I have a takeIntReturnDoubleArray method in this C# library that takes an integer and returns an array of doubles. All I need to do is have a C++ method that takes an integer, calls the C# library and returns an array of doubles to the calling application.
So in essence the C++ library is just acting as an intermediary between the C# wrapper and the external application.
Is there an easy way to do this? Do I have to do anything special on the C# side to allow it to be imported into C++ easily? I have seen some talk of using the #import statement but I really have no idea what I am doing when it comes to C++.
What is the approach I should be taking here?
You have two main options here:
C++\CLI - this allows you to have both managed and unmanaged code in the same source file. The managed portion can then call the C# code.
COM Interop - expose your .NET type as a COM interface and matching coclass which you can easily use from unmanaged C++.
COM Interop is one way to approach this problem. You'll have to have a COM layer for the C# library function(s) you want to expose to the C++ application. This (http://msdn.microsoft.com/en-us/library/aa302324.aspx#usingframeworktools_topic10) might be of interest.