I've read many solutions to the issue of using C# code in a C++ project, including this one: How to use c# code in C++ project
I've also read this, and one answerer says Compile your C++ code with the /clr flag. With that, you can call into any .NET code with relative ease.
Does this mean that I can use C++ & C# code together, within the same project if I append the /clr flag?
I'm a little confused by this, and it'll just waste time if I went the long route of converting the C# project that I'm trying to use parts of to C++, if doing so isn't actually needed.
Basically, I answered my own question on a different topic a couple of days ago without realising that the actual code of the sample project is C#:
Obtaining Current Network Rate
Can anybody give me a firm clarification to whether I understand this correctly (that I can use C# code in a C++ project with no issues, apart from the /clr switch being required)?
I'm not sure if SO is the right place to ask a question like this, so please tell me if it isn't instead of downvoting with no explanation.
Thanks.
Edit
Forgot to mention that this is a C++/CLI gameserver application DLL on Windows. If it matters, it is used on only Windows Server 2008 R2 and Windows 7.
If you use C++/CLI, then you can add references to other .net assemblies, but you do not mix C++ and C# code in the same project. What you would do is to create a new project (or add an existing one) in your solution using C#, and then add a reference to it in the C++/CLI project.
The drawback is that you need to marshal between C++ and .Net types (std::string vs System::String^), and you also need to learn the additional syntax used by C++/CLI (^, gcnew, etc.).
Further reading: Pure C++: Hello, C++/CLI
It means, that with the /clr switch, you can access assemblies (DLL or EXE) written for the .Net framework. Because such assemblies can be created with any .net language (including C#), you can use "code" written in C# from within C++, but it doesn't mean that you would be able to write C# in C++ project. Unfortunately - you can't.
You need to make a C++/CLI project in visual studio.
C++/CLI is a bit different to C++, because there is the managed stack, so memory is managed and you can avoid memory leaks (garbage collection).
Simply create a C++/CLI project and click on propietys and add a reference to your C# project, it should work :D
http://www.codeproject.com/KB/cs/ManagedCOM.aspx
Related
I was working on a windows form project lately and I made some functions in that project that I want to use from another c++ project of mine. My windows form project is creating a .dll already, so I was wondering if I could call my functions thanks to it somehow.
I tried creating a CLR empty project as I know those are supposed to link C++ and C# possible but when I try to use the namespace of my C# classes in the CLR project, visual doesn't find it and tells me the name I'm trying to use must be a namespace, am I missing something?
Here are some images of what I've done:
Encrypter.cs (the C# class I'm trying to use)
The C++ file in the CLR project trying to use it (I tried several ways of getting my class, I left them all, none worked)
Both projects are next to each other in the same solution.
To sum up my questions:
Do CLR projects work both ways with C++ and C#? I find very few mentions of C++ projects using C# functions, but much more of the other way around.
Is it possible to call windows from C# functions from a C++ or CLR project, or do I have to make another C# project that creates a .dll ?
If I'm going the right way with what I've already done, how do I use my C# class in my CLR project?
EDIT: For anyone maybe coming through here, I found the solution. Turns out I did miss something in my setup, when selecting the CLR project and going in the "Project" menu on top of visual studio, you can then go to "Add Reference" and select your C# dll. Once I did this, the CLR project saw all my C# classes and functions.
I have to use a third-party dll in my C++ project. All I know about this dll is that it was built in Visual Studio 2013. I use VS2010 and can not switch to 2013 because reasons.
Said dll exports some functions that return std::string. Unsurprisingly, calling those functions produces an access violation in some string deallocation code.
As far as I understand the problem, that's nothing to be surprised of, also nothing that could be done about other than switching to VS2013, which I can't.
Here is the thing though. This third-party dll comes with a c# example project that imports it and works just fine!
So my questions are:
(purely theoretical one) Why? Is it .NET string marshaling magic at work?
Suppose I wrap the offending dll in a managed dll of my own, then use that managed wrapper in my unmanaged code. Will it work?
If the answer to question 2 is yes, then how? I know literally nothing about c# so i wouldn't mind a few pointers.
EDIT:
So out of pure desperation I tweaked the imported function signature in my project - it was std::string (__cdecl *TFunc)();, changed it to BSTR (__cdecl *TFunc)(); - and it works! even though both library manual and the dependency walker tool insist std::string is correct. Posting this as an edit and not an answer because I still don't know what's going on here and it is scary.
I have a windows forms app written in C++/cli. I want to extend this app with some new forms and I'd like to create them in C# in a separate project.
Is it possible to simply add a C# project to a solution that has the C++ project and the two will interact? By interaction, I mean that, say, a button clicked on a form written in the c# project will be able to call methods in the c++ project. Asked perhaps in a different way, can an object in the C# project reference an object in the c++ project? if so, do you know of an example code to get me started?
Thanks.
Yes. A C++/CLI application will be able to interface with a C# application, in one of two ways:
If you are using CLI extensions (which from your post it sounds like it), you will be able to write code using the new object references:
Managed objects: System::String^ myString (in C++) is the same as string myString in C#
Managed refs: System::String% myString is equivalent to ref string myString.
If you want to use C++ native types, then you will have to use P/Invoke, but that's an entirely different category. For what you want to do, just add the C++ project as a reference to your C# project, write a publicly-visible class in C++ using managed types, and then compile. Your project should then be visible to your C# class in whatever namespace you chose for the C++ class.
EDIT: oh, and if you need to allocate managed objects through C++, you will need to use gcnew instead of new.
This can be done by compiling a dll with the C++ project, then having the C# app load that dll and then it will be able to call its exported functions. This method allows your C++ code to be unmanaged code.
As far as finding a sample that is already set up, I can only find a Visual Studio 2008 project:Microsoft All-In-One Code Framework
For visual studio 2010, here's how to do the C++ side: How to make a dll with C++
Using Explicit PInvoke in C++
I am trying to call a dll file from c#
The dll file is made from a java application using ikvm and for now all the code does is print hello world.
How do i call the dll file in my c# code and is it possible to create an application in java that will return a boolean value to my c# code?
Thanks for your time.
I'm not sure I understand what you're trying to do, so apologies if I'm misreading. IKVM should translate your java code to a .NET dll or executable. After the "translation" you should be able to use the .dll more or less in the same way as you would with a "native" .NET code.
If your java application has a main method that prints "hello world" on the console, you should have converted it to a .NET executable (.exe) and not to a dll.
After converting it to a .exe (and assuming you're running it on Microsoft .NET on a windows system) you should just execute it.
As for the second part of your question, you can also create a dll (converted from java) that returns a boolean and consume it from a C# application.
See this tutorial for two examples of (pretty much exactly) what you're doing.
using System.Runtime.InteropServices;
You can then use
[DllImport("myjavadll.dll")]
Then add the dll as a reference by right clicking and navigating to it in the reference folder.
EDIT:
Here is a link that calls a C++ dll to C#. You may be able to work it out.
Call another languages DLL
EDIT: I have had issues adding DLLs as references and was forced to add as a resource. I believe this was because I was working with a sys32 dll.
Here is an old post by where I was trying to work out some DLL import errors. Maybe itll be helpful if you encounter some problems.
Old Post
How can I convert my C# code to DLL file in a way that the user of DLL can’t view my source code?
When I make DLL in the way I always do by making a class library project, importing my classes and compiling it, the source code can still be viewed.
I believe you are looking for an obfuscator. This is a tool that will take a compiled DLL and rewrite the code with the intent of it not being meaningfully decompiled by another user. Visual Studio comes with a free Dotfuscator
Note, this will not actually prevent people from looking at your code. They will instead be looking at a very weird translation of your code. There is no way to prevent people from looking at decompiled versions of your code in C# or any other .Net language for that matter.
This is not something that is unique to C#. It is fact a flaw of every language in existence. It's perfectly possible to decompile C code. The difference though is it's much easier to maintain a lot of the original code structure when decompiling managed languages (.Net and Java for instance) because the metadata maintains the original structure.
obfuscation is what you want to search for.
There is a free one (that is limited) in visual studio called Dotfuscator.
Uses fancy methods to rename your code and alter flowpaths to obscure it.
Consider using an obfuscator.
If you are developing desktop applications converting your code to Dll will not hide the it( there are many tools to decompile the dll or exe files).
but if you are using Asp.Net, then you can compile your site to Dll, and the code will not be visible in the aspx pages, it will be compiled to Dll, you can do that by right click on your project on solution explorer, then choose Publish website
But in all cases .Net Exe files and DLL will be easy to decompile and extract the source code again, unless you use tool to obfuscator your code.
If you mean, the end-user can view your source code by decompiling it, you can protect yourself using an obfuscator.
There is standard obfuscator build in into Visual Studio. In the menu choose Tools / Dotfuscator community edition.
I think my reply to a similar question about JavaScript obfuscation applies here as well: in short, why bother? Your question has already been answered here ("use an obfuscator"), but I thought it wouldn't hurt to find out what your motivations are. Generally, code that you give to people is "in the hands of the enemy" -- if somebody wants to use it/figure out how it works badly enough, they will.