I have C++ application which has UI developed using MFC, does some networking using sockets (using boost libraries) and some image processing. I want to move this application into Silvelight framework (I can use 4.0 if required) so that it can be used over the internet easily. Here I want to move all parts (UI + networking etc) in to C# but keep the image processing code in unmanaged C++ only. I don't know .NET framework yet, but whatever I have read so far suggests that it is not possible to call the unmanaged code from a silvelight web application. Is my understanding correct? Can something be done to achieve what I am trying to do? Also, if somebody has some suggestions on how to go about porting the code?
Silverlight 4 supports COM when running in trusted mode.
So, tecnically you could have Silverlight call your c++ library using COM.
The main problem I see is on deployment and I don't think it's a good idea.
Also, remember that Silverlight can run on Macs but COM is Windows only.
What you could do is to have the image processing happening on the server, but then you
can run into scalability issues.
Transfering large amounts of data between client and server can become an issue.
UI response should probably be closely evaluated too.
Regarding porting the code, well, you are most certain looking at a complete rewrite.
I'd suggest using WPF instead of Silverlight if possible. With WPF you'd be able to reuse your C++ as is because desktop .NET / unmanaged interop is very good (P/Invoke or CLI/C++).
Otherwise you are stuck porting your C++ to managed code, which could prove to be laborious and the resulting code inefficient.
Related
I hope that question would not mess with StackOverFlow FAQ rules
So ,when using Libraries which are written in C++ for example ,and that means we have some Code in these DLL's which is going to be executed ,when Software execution cames in that case ,will this Portion of code be executed by CLR ?
I need that because we plan to develop a Software and some Angry Algorithms i think will be better to program them in C++ ,but Visual C# serves us some tools that we cant find in c++ (Linq ,Anonymous etc) .
You can use DLLs created in C++ inside your C# project, and as you already know you have to make an interop call. This switches context to unsafe, so the code is probably executed outside the CLR. This means that you lose the portability options the CLR gives you. For example a C# based app would run on Windows and Windows Phone, but adding interop calls will only make it work on Windows (or whatever system the DLL was compiled for).
But normally this isn't much of an issue.
Also see this thread: http://forums.devshed.com/net-development-87/using-a-c-dll-in-c-107829.html
I have a game server which is made in Java. I want to make a plugin system that loads a .NET DLL and calls events / functions inside that DLL, then inside those I'll have to call functions in the game server (Java). The only part that is giving me trouble at the moment is how to interface java and a .NET dll.
I've been searching and found some things but they were all based on products and I want to make my own interface for that. Ah, not to mention it needs to have high performance, the code will be called a lot of times in a second if it has to. Could someone point or give-me ideas how could I work this out?
EDIT:
To make it more explicit:
Game Server (Java application) calls a function in .NET dll
The .NET function just called by java, calls multiple functions from Game Server (Java Application).
Take a look at jni4net if you're targeting Windows. It's an alpha quality release, but Robocode already uses it to run .NET robots inside the Java runtime.
Another option is to use a high-performance messaging approach. You'll need a second process - likely a .NET plug-in host. That process then exchanges messages with the main Java game process. Messaging libraries like 0MQ are pretty darn fast but may not be fast enough for what you have in mind. In addition, you'll have to create a lot of message plumbing which may be cost/time prohibitive.
Try using iKVM:
IKVM.NET is an implementation of Java for Mono and the Microsoft .NET
Framework. It includes the following components:
A Java Virtual Machine implemented in .NET
A .NET implementation of the Java class libraries Tools that enable Java and .NET
interoperability
http://www.ikvm.net/
If you only have a few methods you are calling you might just use JNI and do it yourself instead of a 3rd Party tool (though I admit I don't know the details of jni4net). Just a word of caution, the project I'm on had to do a similar thing (C# -> C/C++ -> Java via JNI) and we had nothing but problems with it. Problems mainly because the java api didn't have any good documentation so that might have been part of it. If at all possible try to keep it to one language but if that is not possible, make sure you do lots of error checking. When the app crashes, it is very hard to find the problem (unless you own both the java and C# sutff). Just my $0.02...
While doing Windows Mobile development, which language should I use? C# or C++ or something else? Why one is better than others?
It depends what you're coding.
Making native calls to the OS are possible via P/Invoke from C#, but extensive use is probably easier via native C++. You'll also require C++ for using some hardware that has not been wrapped by the Compact Framework.
Most hardware (GPS, camera, etc.), is available via CF. If you're working with a Win Mobile 6.x device, you're probably better off with C#. In addition to hardware, Pocket Office's (POOM) object model is also available to C#, so you can integrate with it.
It's worth noting that most references to Windows Phone 7 refer to managed code and the possibility of Silverlight. With Silverlight in the mix, you'll have to code with C#.
Unless your app is high performance or is extremely miserly with memory, use C# or VB.NET.
Scott
It depends on task mainly.
c++ has following pros/cons:
Direct access to resources, faster programs
Can access very deep OS parts, not needed for high level applicaiton
harder to develop and requires to manage resources by developer
C#:
Runs under virtual machine (CLR), that's why is slower
Faster and easier application development
Rich build-in library
There is no right answer for this, becasue there is no one-size-fits-all "better" definition. If you know C++ and have a lot of C++ code assets already, C++ sure looks appealing. If you know c# and not C++, then C# sure looks appealing.
C++ applications load faster, but for many applications, that's not relevent. C# applications can certainly be written faster, but they also don't have determinism. I'd never even attempt a UI in C++ any longer, nor would I think about doing database access in C++. I wouldn't write a driver in C# though, or a shell extension.
Generally speaking, most solutions I've ever delivered were a mix of the two. C# has its strengths. It's fast to write, easier to debug and unit test, hard (though not impossible) to create leaks and for some operations (like data access or XML parsing) it's just easier.
C++ has its strengths too, like speed of execution (though C# can be made to go just as fast for many things), determinism and the ability to plug in to things that want native entry points.
So my answer? You need to know both, and likely write your solutiuon using both. The percentage of each you end up using depends on what your end goal is.
It depends.
At least present a specific use-case. And possibly use SO search? :)
C++ or C# to program mobile barcode device?
Edit:
Apparently others were faster to the draw, and gave more articulated answers. Nevertheless, I still recommend reading the above SO thread.
From my experience it is easier to start with c#, and if the api provided by the compact framework is enough for you then you are ok.
On the other hand if your project is somewhat complex, or if you want to do something that is not in the compact framework you may end needing to create a helper .dll in c++. Even in this case you maybe good doing your main program in c#, and programming helpers dll in c++.
If you go directly to program in c++ you may benefit from the fact that you have a raw performance better than c#, which is good if you are doing a game.
But you will also suffer more from the limitation of windows mobile OS. Like a maximum of 32MB per process, or that all .dll share the same address space.
So in the end it really depends on what are planning to do and the experience you have.
I am working on an application suite comprising of multiple Automation servers written using MFC and this is legacy code. These apps inter communicate via COM interfaces and other events. Most of these apps provide multiple form views with various input controls to capture information. I was wondering what would be the best way to migrate these applications to managed code one app at a time. Any advice...
We work in native code, but porting the code base to managed world is my personal idea because I can see a lot of functionality that can be achieved in a better way if the code is written as managed code.
Thanks,
Byte
You could write new parts of server using C++/CLI. It looks like a less painful option.
I have a solution with 2 projects:
a c++ main project
a c# project (display simulator)
Today these 2 apps share data using a loopback TCP client/server connection, but that's not very optimal (timing issues..).
I was wondering if there was a way to access the c# data from the c++ project directly and vice versa? (It seems to be possible with 2 c# projects..)
If it's not possible, what's the best way to implement this with shared memory?
thanks!
Michael
EDIT: thanks for the answers. The 2 projects used to be independant solutions and are both executables - I'm actually trying to merge the 2 into 1 solution / executable.
For info: The c++ app is a PC version of an embedded app - the c# app is a lcd/HMI simulator.
Converting the C++ project to a C++/CLI project might be the easiest way to go. Note however that some code doesn't play well with C++/CLI (we've had problems using libraries that use boost::thread in a managed executable).
You can use COM Interop or Platform Invoke to access native code in C#.
If that's not what you're asking for, please elaborate.
Named Pipes?
For interprocess communication via named pipes you can check out the .NET 3.5 feature
http://msdn.microsoft.com/en-us/library/system.io.pipes.aspx for the C# side. From the C++ side, I assume you know the equivalent :).
There are two ways I know of to get direct access to memory between c++ and c# without the overhead of marshaling/demarshaling and com. If it is required to keep the c++ part of your code native then the only way I know to achieve this is to host the clr from your c++ application. A relatively complicated undertaking. Google "hosting the common language runtime". Then you can load your c# code as an assembly, call into the c# code and provide a common shared memory style interface. Although you will have to write all of the shared memory support yourself as I have found no direct support for shared memory in c#/.net.
The other way is to compile your c++ code with common language runtime support. This is by far easier and will allow you all the power and glory of c++ while allowing access to clr based data types, and the ability to call back and forth between your c++ and c# code. See "Language Features for Targeting the CLR" in your VS2008 documentation. pin_ptr will become your close friend and ally in this process.