Clarification. There is a C++ exe and a C# exe. The C# exe is a wrapper for a C# dll. I need the dll to call a logger function in the C++ code (so that only one log file is produced). Currently there is a c++/CLI bridge which allows the C++ exe to call methods in the C# dll.
Apologies if this is a poor question. Its possibly a case of I just don't know what to search for / results for what I am searching for isn't of much use.
I have an application written in C++. It calls a tool written in C#. It appears the executable for the tool is just a wrapper for a c# dll.
The tools purpose is to analyse and display data. The main application calls it for example to have it open a new file. The tool has never had to call anything in the C++ code before so this has always been one way. It appears to be implemented via a C++/CLI bridge. The bridge calls the functions in the tool api.
It is now required for the tool to call some methods in the C++ application. I have no idea how to go about implementing this. My c# / C++/CLI experience is somewhere between poor and non-existent. I started by attempting to clone the C++/CLI bridge and "reverse" it, but since the C# code is in effect a library calling it from the bridge is fairly simple.
However, i'm not really sure (if its even possible) how to call the C++ application from a bridge.
So far the only workable solution I can think of is to have the c# code output to a file (or hopefully shared memory) then the c++ code check it periodically. This isn't close to ideal.
Any advice would be appreciated.
Thanks
Ok, i think i'll throw in a suggestion here.
Depending on what your goal is:
1) Goal: execute some of your c++ logic from c# code.
Solution: this one is fairly simple. You extract logic of interest into separate C++ project, build it as a library and then use it in both applications. As you said, there are plenty examples on how to call c++ dll from c# code.
2) Goal: froce your c++ application to execute some of it's logic from C# application.
Solution: it all comes to setting up an interprocess communication. There are quite a few approaches, that are listed here. I suggest using NamedPipes but you are free to pick w/e you are comfortable with.
Edit: Judging by your edit you probably want the second solution.
Related
Is it even possible to create GUI layer in C# and rest of application in C++? If I am not wrong one of antyvirus software had GUI made in Delphi. How it could be done ?
You have several options for doing it, including:
Use P/Invoke to call into the C++ DLL from C#.
Expose a COM interface from the native code, and call it from C# using COM interop.
Write a native Windows service and call into it from managed code.
Use C++/CLI to write a managed library in C++, which you can easily link to from C#.
If you're starting from scratch, option 4 is probably your best option. (Aside from just writing the whole thing in C#, that is.) The first three options all involve some additional wrangling and overhead, and probably aren't worth the hassle if you don't have a compelling reason such as needing to interact with an existing native library or having some need for a service-oriented architecture.
If you write your business logic in C++/CLI, and your UI in C#, it shouldn't be a problem. If you want to write in pure ANSI C++, you might have to write C++/CLI wrappers around the objects you want to expose to C#.
write the app logic in c++ dll, then use pinvoke from c# to talk to the dll.
See this answer. It seems to answer your problem
Can Delphi 4 and\or 5 application functionality (.exe) be integrated into a C# application?
I've been tasked with rewriting a new application which will be based off of existing Delphi 4/5 written application, which are currently held together with a Batch Processing Script that no one at my company understands.
As an interum solution, I've been asked to investigate whether a C# GUI\wrapper can be placed on top so it's easier to maintain and run.
I know that Delphi 6 applications can be called within a C# application using reflection but I'm not entirely sure how.
So back to my original question can a Delphi 4/5 application functionality be called within a C# application?
Thanks in advance.
The underlying premise of the question appears to be that a C# wrapper around a Delphi core is easier to maintain and run, and if that is not true, then the idea of creating the wrapper becomes not-very-useful. I believe it is a wrongly-conceived notion.
Imagine that I made an application that can talk to a telescope. It does it perfectly. In that case, I might be able to extract just the telescope-communication part and put it in a DLL and then write a user interface in C# that uses the Delphi DLL just to do the communicate-with-telescope task. However, unless your Delphi application was already structured in a nice way, and unless a task like this telescope-communications library already exists, you won't find it very easy to extract any part of a Delphi application, and use it from C#. If that situation existed, I would use native Delphi DLL function exports and invoke them from C#. This is not using the existing delphi executable, and requires many hours of work to refactor part of a Delphi application into something that could be used from C#.
Another answer mentions COM Servers, and while that is possible, it is not going to make things easier; Like the old joke about regular expressions; When you have a problem and try to solve it by using regular expressions, now you have two problems. The same becomes true when you try to use COM Servers to hide your existing application and write a whole new UI on top of it using C#. It would actually take more technical skill to improve, debug, and continue to develop it that way, than to keep developing it either purely in delphi or purely in C#. It's a negative savings of effort.
You have given no information about what the Delphi application does, but let's assume that it's a line-of-business or vertical market application that reads some file format, or does some communication protocol, or even connects to some old database, that you don't want to rewrite.
If by making the C# UI you mean, to never show the Delphi application user interface and replace it with a C# one, it is nearly certain that your idea is not going to make anything any better, and can only ever make things worse. Your deadlock either comes from not having skilled delphi developers, or else it comes from not having clever developers who can figure out what an existing application does.
The solution is usually a human solution when you are in this situation; either to hire a skilled delphi developer and bring the application forward into the modern Delphi era (Delphi XE2) or to hire a skilled non-delphi developer and port the application to some other language. Anybody who would suggest writing a "wrapper" over top of the delphi application who thinks that will make it "easier" obviously feels incapable of rewriting the existing application.
I don't know enough about what your delphi application does, to be sure, but it sure sounds to me like "fear driven" decisions. Wrapping old code is almost never a good idea, and is most often, just the creation of more problems.
A Delphi .exe can be run from C#. But I guess this is not your point.
You can either use a COM server, which is standard but needs the COM object to be registered on the computer (by running regsrv32.exe). Not so easy to deploy.
Or you can define the Delphi code as a library, then load and execute the .dll from the C# code.
If you prefer to access C# objects from Delphi 4 or 5 (that is access C# RTTI), you'll have to use some low-level unit like Managed extensions for VCL - .Net interop for Delphi Win32. Which is quite complete, and works with old versions of Delphi (whereas something more high-level than Hydra will not support Delphi 4 or 5, sadly).
Edit
Another possible easy communication is GDI messages. You can send GDI commands from your C# code to control the Delphi application, but using PostMessage() API calls.
Sure. C# can call any .exe. Just use Process.Start:
http://www.dotnetperls.com/process-start
http://msdn.microsoft.com/en-us/library/system.diagnostics.process.aspx
Delphi 5 supports implementing COM server functionality (don't know about earlier versions, D2 definitely did not).
If you have the sources available,
add a type library and a COM implementation of the interfaces defined in the type library,
register the executable (typically done automatically on startup thanks to Delphi magic)
follow the steps on MSDN: Exposing COM Components to the .NET Framework
My question is what's the best way to create an inteface with C++ code.
Basically so far I have a console project in c++, that works as I expect to, but I now want to make a GUI for it. The choices to me seemed to be:
Make a dll of the c++ project, and then make a C# form which uses the dll to do the logic.
Same as 1 except with VB.
Use QT or something eqvilent and make the inteface in the same project.
I've been trying option 1 for quite sometime. I made the library I believe successfully by making a library project in Visual Studio 2005. I then put it in my c# project but I then had a problem of being able to instantuate my class, but the c# project couldn't see my methods.
The only fix I could find to this was to use the ref keyword. The problem with this was then not being able to mix managed and unmanaged code and trying this on one of the larger classes produced about 250 errors.
Option 2 i had the same problem with.
I'll start option 3 if I have to, I just wondered if I was missing anything fundamental or any suggestions in general?
Cheers for reading.
You absolutely can use C++ code from C#, but if it's unmanaged C++ code, you have to delve into the realm of pinvoke to call your code.
If you're attempting to leverage an existing C++ library from .NET, one of the easiest ways to do this is by using C++/CLI as a wrapper around your unmanaged library. C++/CLI compiles into .NET bytecode, but features lots of automatic unmanaged interop. A phrase that's often floated about when using C++/CLI unmanaged interop is "it just works". It's an accurate phrase.
Once you have a C++/CLI wrapper for your unmanaged code, C# should be able to see everything exposed by your C++/CLI library.
I have a (header only) C++ library that I am looking to port to C#. It is a wrapper of the win api which I have made for a certain purpose. I want to port it to C# because I want to develop it further using C#. What is the most efficient (and easiest?) way to port it. Please note that I do not want something hectic because I don't want to spend more time porting the library than it took to make that library in the first place. So is there a way?
It depends very much on how big your lib is, how it is structured, how your memory allocation looks like, how much you made use of libs not available in C# (like the C++ std lib), how much C++ template programming you have used etc.
Different strategies may be
try to port (parts of) it automatically by some code generator of your own
do not port it to C#, instead use C++/CLI (something I did very successfully in the past)
do it manually because the C++ concepts you have used so far don't map well to C#
"Header only" does not seem to make a real difference. In fact, things may technically get a little bit easier when you have just one C++ file for each class to be ported to one C# class file.
A couple of ways I can think of.
Manual conversion to C# dll with possible code generation help of T4.
Change your c++ library to a managed dll so you can use it in your c# project.
Of course, you might use interop with your c++ library in your C# project. But in that case, I am not sure about purpose of your c++ library since you said it's a wrapper.
Since you already have c++ library that you can fully control, I would try to go with #2 first.
Is there a way to call c# dll from c++ unmanaged application without COM usage?
You can do this using Reverse P/Invoke - example and discussion here.
It is actually possible to disassemble, modify the IL, and reassemble it with exported functions. I messed with this a few years ago, and created an application that would disassemble a dll, provide a list of functions that could potentially be exported - allowing the user to select them, then re-write the IL and reassemble everything. Then, I could call directly into the dll from unmanaged code...or p-invoke into the dll from managed code (not really practical, but interesting nonetheless).
Surely there is a reason that this isn't supported in the .net languages themselves (even tho it is supported in MSIL). I wouldn't use this in production:
Dead link:
http://www.csharphelp.com/2007/03/exporting-managed-code-as-unmanaged/
Wayback Machine:
https://web.archive.org/web/20140213030149/http://www.csharphelp.com/2007/03/exporting-managed-code-as-unmanaged/
I might be a bit late, but check this out.
Using this little msbuild task, you can create a C# library that can be called as if it were a native DLL. (e.g. write plugins for apps that require them to be native dlls)
Oh and don't forget to use the project template, which will setup everything for you.
Your only option really is to either use C++.net or create a C++.net wrapper for it that exports what you need.
Calling C# code from C++