I have a dll file that was made in C++ and i need to connect it to my C# winform app to use different methods from there. I tried to give a reference to it as I done before with ordinary C# dll's but there was exception about it, because of wrong format of the dll.
After that i tried to use DllImport as i was recommended and it's works pretty good. So, my question is, is the DllImport is only solution at this situation ?
The short answer is Yes, [DllImport] is the way to import native methods.
There are others like a C++/CLI wrapper or COM, but they are more work and less fun.
Related
I'm noob in C# and I already searched on the web. Anyway I'm still not sure about this and I do not have the total control of the code I have to implement, this is why I would like to be sure I needn't make any dll. I have a C++ file with a method, and I want to call this method from C# code. I just added "extern C" to the function.
When I just add the .h and .cpp files to the C# project they aren't detected. And of course, when I try to add it as reference, it doesn't work.
So do I absolutly have to make a dll ?
Your options for accessing the C++ code from C#:
Compile C++ as unmanaged DLL and access using p/invoke. This requires the C++ code be exposed using a C style API.
Compile C++ as unmanaged DLL and access using COM. This requires that you wrap your C++ in as COM objects.
Compile C++ as mixed/mode C++/CLI assembly and access the assembly as a managed reference. This requires that you wrap the original C++ as managed C++ ref classes.
All of these options, by necessity, involve the creation of another module/assembly. You cannot link the C++ code directly into your C# assembly.
You might like to try using the PInvoke Interop Assistant to generate the C# necessary to interact with the DLL via Platform Invoke. Be aware that this is imperfect though so YMMV.
Another alternative, if you have the knowledge and patience, is to make a COM component out of your native C++ DLL and consume that from C# by using the Type Library Importer to create a managed wrapper.
You won't be able to interact with .cpp/.h files since you need at least a binary object (assembly) for C# to interact with and C# won't generate any binaries from .cpp/.h. That's on the subject about adding these files as references to the project.
As for the argument that you don't have control over the code - well, don't make a DLL out of the actual .cpp/.h, but make your own thin DLL that has a wrapper object that just includes the headers, calls whatever method you would be calling and links to the appropriate .o files or .lib or whatever you have. If the interface changes you would just changed your thing wrapper which should be easy.
I am doing mine FYP by using the
Visual C#
Agilent VEE
I am try to import the DLL file which created from C# into Agilent VEE but VEE required the header file and library file for the importing.
Please kindly help me.
In C#, there is no header file, this is different from C++! To use old C/C++ code, use PInvoke.
You cannot consume a c# dll in your C++ project and vice versa (normally). You should either create a com aware dll in C# to consume it in C++ or on the other hand, you need to declare all the functions in C# to use from a c++ dll.
Here I am talking about standard dlls (not activex or com all). They require a different methodology to work with.
Perhaps you can avoid the "Import Library" primitive in VEE, and not need a header file.
Use Device --> .NET Assembly References... and browse to your DLL files. Then you have to import or select a namespace. Finally, functions of the DLL appear in the function browser of VEE.
Not all DLL files can be used. I have two similar from a hardware vendor. The one named somename_net.dll works.
If you find an answer to your original question, I'd like to know. My method
I have the c++ source code of functionality which is appealing to me.
What effort/work is involved/required in order to either reference this from a .net application or build this code as a .net assembly (preferably c#)?
This is my first attempt at porting code, so please breakdown your answer for me step by step.
There are several ways of doing it.
PInvoke
Create C++/CLI wrapper around your C++ native code (make static library out of C++ native code) and C++/CLI generated assembly can be easily utilized in .net application.
COM, i.e using interop (which is difficult among all the options)
In my suggestion easiest way is to use option 2, but you need to take care of proper marshaling.
Solution A:
If you have the source code, then compile the CPP program as a DLL file.
Use P/Invoke
Solution B (if the functionality you want is in a static library):
Create a stub function caller and compile THAT as a DLL
Same as solution A.2
I have been looking for a way to call a function written in a C# EXE project (VS 2008) from a C++ DLL project. I can include the C# code as part of the C++ project itself if that is possible. All that I have been able to find is calling the C# DLL from C++.
Ultimately I want to call C# code from VB6 but I ask the question this way because I don't believe the later way is possible without an intermediate step.
Thanks,
Ian
Ultimately I want to call C# code from VB6 but I ask the question this way because I don't believe the later way is possible without an intermediate step.
You can register the C# classes to be visible to COM, and then call them directly from C++ or VB6.
For details, see the Example COM Class on MSDN, as well as Interoperability.
You can compile your c++ project with the /CLR option and then call C# from within it. To do that you need to include vcclr.h and then add a using statement for each dll you need to call from.
#include <vcclr.h>
#using <System.dll>
I'm new on windows phone developement and i have one problem that i don't know how to resolve....
the problem is....
i have a c++ project that i had complided with visual c++ 2010 and this create one dll with code compiled...
so i know that C# import dll libraries but when i add refrences it's make this error "Unable to retrieve assembly fullname ""Parameter name: AssemblyPath" and i dont kown what it means...
I searched on google and i found one method to import c++ dll manualy with DllImport and calling a external method... that causes one error because it's dont find the dll location... it's happens because wp7 don't suport C++???
thanks for help me
Neither P/Invoke nor C++/CLI is supported, only managed user code. See social.msdn.
3rd party WP7 apps may only comprise of managed code. C++ is also not a supported language, even in managed form, at this time.
WP7 doesn't support c++. you would also probably need to recompile the c++ dll anyways, even if it was supported.