This is with Visual Studio 2010, SP1. I have a C++ class in a separate C++ project that I want to access and use in C# from another project (both living under the same solution). I have referenced my C++ project from C#. I build my C++ project using the /clr option. I have built a Managed version of the C++ class that calls the corresponding native C++ class.
When I right-click on my C++ project reference from my "References" of my C# project, and click "View in Object Browser", my C++ project exists as part of the list of objects, and I can open it and see my class, namespace, etc. that I am trying to use.
However, from C# code, when I try to do "using " it's not part of the autocomplete list of namespaces, and in fact it gives a compilation error if I type the C++ namespace. "Error 1 The type or namespace name 'MyCppClass' could not be found (are you missing a using directive or an assembly reference?)"
And the answer to that question is no, I'm not missing a using directive or assembly reference, as explained above. Additionally, my C++ classes don't exist in the default namespace, they simply don't exist in my C# project's universe.
So... what am I doing wrong?
This may be too late, but I just had this same issue as you and came back to see if you got an answer.
Eventually I figured out that you need to actually add your COM class as a reference to your .net project along with the .net wrapper class.
I created a c++ COM dll and used the tlbimp to generate a .net wrapper. I then added the wrapper to my project, and went to add references under the COM tab it had my COM assembly there, so I added that too and my project compiled and worked fine.
Related
The problem I am currently encountering is really weird. I try to use a Managed C++ class from a C# project but the compiler cannot find the type.
Take a look at this screenshot:
The Managed C++ project (NGervill.Gervill.Native) is referenced and according to the Object Browser it contains all required namespaces and types. In my source code I've added the using and used the class but still I get a compile error.
Now the strangest part: The other types within the Managed C++ project can be referenced. In another C# class I access the methods of the PortMixerProviderNative class. That means target platform and .net framework version are correct (.net 4.5 - x86 build).
Is Visual Studio somehow caching an old version of the Managed C++ DLL or what else can cause such a problem?
PortMixerNative is a native C++ class, not a managed class. Native classes can be exposed in the assembly metadata in some cases, usually because they are the type of a private field in a managed class wrapper, but they are not usable in any way from a C# program. Only public ref class declarations in the C++/CLI project are usable.
It isn't clear what wrapper class you are supposed to use. Not PortMixerNative. Check the vendor's manual and/or code samples or contact them if you need more help.
I finally found the solution of this problem: For some reason the cpp file implementing the PortMixerNative class was not included in the project. After adding the PortMixerNative.cpp to the project again I finally could see that there were syntax errors in this file. After fixing the errors and recompiling the .Native project I could successfully reference the class.
The strange thing is that the .Native project successfully compiled even with methods without implementations. If anybody encounters this problem too, check if all methods of the class you try to use have an implementation.
I'm using Visual Studio 2010. I've written a dll in C#, managed dll then.
Now for some reason, I need to write a software in C++ (.NET then also managed).
I need to import the C# dll into my C++ .NET code.
I can't figure out to do this, I've made several search but this problem seems to not be covered. For example, in C# I don't have include file, then how my C++ (.NET) projet knows about classes and functions inside the dll?
Thanks,
In Visual Studio, bring up the properties of the C++/CLI project, go to "Common Properties/Framework and References" in the tree at the left, and click the "Add New Reference" button. This will bring up the standard "Add Reference" dialog you can get from a C# project, just select your C# DLL or reference a C# project in the same solution.
You need to add a reference into your project. In Visual Studio, right-click your project, then select "References".
You add reference to you assembly, Set ComVisible attribute to your assembly
Edit your AssemblyInfo.cs
[assembly: ComVisible(true)]
.Net Framework have MSIL langage in order to manage interoperability betwwen different langages
Link : http://support.microsoft.com/kb/828736
You just need to add only reference of that dll in your project, as George has replied.
then use that namespace or name of classes in your code...
It is possible. Google search would gave you answers. Few links from Stackoverflow
How to use c# Dll in vc++?
using c# dll in project c++
and you get many more links https://www.google.co.in/#sclient=psy-ab&hl=en&site=&source=hp&q=using+c%23+dll+in+vc%2B%2B&oq=using+C%23+dll+&gs_l=hp.3.2.0l4.1601.6409.0.9065.18.13.2.3.3.2.468.2716.0j9j1j2j1.13.0...0.0...1c.1.ixoWIPWicqo&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=64f4e49ac7d1c408&biw=936&bih=595
Hope this helps
IDE: VS2010
Framework.net: 4.0
I created a c# dll project under Visual Studio 2010, with several public classes, and I would like to use its classes inside another dll project, but written in vb.net.
In the vb.net dll project, I referenced the built c# dll, but impossible to import the c# classes. The namespace of the c# dll is even not recognized.
What must I do to see my c# classes?
If this is possible.
Example of class of my c# dll (namespace MyCSharpDll):
namespace MyCSharpNamespace {
public class MyCSharpClass {
public void Test() {}
}
}
Example in a file of my vb.net dll:
Imports MyCSharpDll.MyCSharpNamespace
VS2010 indicates an error saying that MyCSharpDll is unknown or no public member.
Thank you.
I think you should rewrite your imports
Imports MyCSharpNamespace
without 'MyCSharpDll' part
You asked: "I created a c# dll project under Visual Studio 2010, with several public classes, and I would like to use its classes inside another dll project, but written in vb.net."
YES you can do it.
Just add to that DLL reference and that's it!
Assuming the dll in question is CLS compliant and compiled against the same runtime version, you should be able to use it without a problem.
If either (or both) of these conditions are not met, you will not be able to use the imported DLL.
Make sure the Import directive uses the namespace as defined in the assembly metadata - look at your C# project properties to see what the default namespace is, that's what you need to import.
You need to add a reference to your C# dll.
http://msdn.microsoft.com/en-us/library/wkze6zky%28v=vs.80%29.aspx
Now you can instantiate a C# class from VB.NET:
Dim cClass = New MyCSharpNamespace.MyCSharpClass()
I have one C++/CLI project, a GUI application, which is compiled in mixed mode (managed+unmanaged).
Now I want to write a custom user control using C# and compile it to become CSharpA.dll.
my question is: Can this dll be used by my C++/CLI project easily? How would I do that?
Yes. Just add a reference to it. You may find yourself wanting using namespace directives, which, like the C# using directive, will add classes in other namespaces into the search space.
You only have to compile your C# code into an assembly, and this assembly can be referenced from your C++/CLI App as any other assembly.
I have a DLL that I've been using with no problem in Visual C# (simply adding the reference and using the namespace). Now I'm trying to learn C++, and I don't understand how you reference a namespace from a DLL. I can right-click on a project and select 'references' and from there click 'add new reference', but that just provides me with an empty 'projects' window. What am I missing?
C++ is a lot different from C#/VB.Net when it comes to processing DLL references. In C# all that is needed to do a reference is a DLL because it contains metadata describing the structures that lay inside. The compiler can read this information such that they can be used from another project.
C++ does not have the concept of metadata in the DLL in the sense that C# does. Instead you must explicitly provide the metadata in the form of a header file. These files are included in your C++ project and then the DLL is delay loaded at runtime. You don't actually "add a reference" so to speak in C++ but include a header file instead.
Once the header file is included, you can then access the namespace by including it in your CPP files
using namespace SomeNamespace;
First of all, if you are trying to use the same DLL you used in your C# application, if you are using pure native C++, it is not straightforward to make calls into that DLL. The problem is the DLL you are referencing in C# relies on the .NET framework in order to execute (it is a "Managed" DLL, as all C#, VB.NET and C++/CLI assemblies are). There is an easy way to reference "managed" code from C++ and that is by making a managed C++ project (AKA C++/CLI) (choosing from "CLR" section in the C++ project wizard in Visual Studio). Otherwise the only way to access the managed DLL is by exposing it to COM and using COM to access the object.
EDIT: The previous answer will be more helpful if you're using unmanaged c++; I assumed because of the C# reference that you were targeting managed C++.
The 'Add Reference' dialog should have a series of tabs - 'Projects' lists projects in the current solution; .NET lists the libraries installed in the GAC and 'Browse' lets you find a DLL yourself.
If you just want to add a reference to the DLL you should be able to do it with 'Browse'. If it's the output of a project you have the source to, add the project to the solution and it'll appear under the 'Projects' tab.
If this doesn't help, which version of Visual Studio are you using, and where/what is the DLL you want to use?