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?
Related
I wrote a Win32-DLL (with clr support in VS 2010/13, c++) as extension for another/old VB6 app and use the opensource-dll PDFSharp.
It works fine, but if the "PDFSharp.dll" removed from Directory the Application crashes if the program try to load my dll.
I want to include the Sharp DLL into mine, so that only one DLL is needed.
I tried to add it to resources, and load/catch the error during run time by
AppDomain^ root = AppDomain::CurrentDomain;
root->CurrentDomain->AssemblyResolve += gcnew ResolveEventHandler(MyResolveEventHandler);
in the first Function that the app calls, but my Problem is, the app/dll crashes before i can handle something.
ILMerge can't help, because it is a Win32/net(clr) DLL not a 100% NET-DLL.
C++/CLI mixed-mode DLLs have two sets of references: the native imports in the PE header, and the .NET assembly references. Problems finding the native imports will cause the symptom you observed, that loading the assembly fails early during load and cannot be intercepted and recovered.
It's not clear to me why the native dependency rules are applicable here. For a true native dependency that needs to be located using an alternate search order under your control, delay-loading could be applied. But that can't be used with a referenced .NET assembly.
In any case, the simplest fix is to not need a separate assembly at all. Your goal is single file deployment, and the ideal single file deployment scenario is when all the code is contained in a single DLL and you don't need to unpack a second file at runtime.
For pure .NET assemblies, there is an ILMerge tool that combines multiple DLLs into a single file. But your case has a C++/CLI mixed mode DLL, not pure MSIL.
Using multiple languages in a native program generally works a little bit differently. Instead of producing a complete executable from each toolset, native code standardizes an object file format (Windows .obj, Linux .o) which all the various toolsets know how to produce, and then the link step can link together object files from a variety of languages. The object files are often bundled into static libraries. (A static library is just an archive of object files, with a symbol index) Because the C++/CLI toolset is patterned on native C++, it uses this model as well.
The .NET version of this language-independent "object file" which can be further linked is a .netmodule file. Internally, it is a .NET assembly without a manifest. Functionally, it acts like a static library. And the C++/CLI link.exe can link together C# (and VB, and F#, etc) .netmodule static libraries together with the C++/CLI object files and static libraries, and native object files and libraries, when it creates the mixed-mode assembly.
This isn't the most straightforward process, because while it is supported by the underlying toolchains, the Visual Studio project options dialog boxes don't have a UI for either creating or consuming .netmodule static libraries.
For the C# side to produce a .netmodule, you should open your .csproj file and change the <OutputType> setting to module. Then reopen the project in Visual Studio and build as usual.
On the C++/CLI side, the project options dialog allows you to customize the compile and link command-lines. Change the linker command to include /link and the name of the .netmodule file.
If you've done it right, the C++/CLI linker will create a single mixed-mode DLL with all the types and code from both the C# and C++/CLI source files. And all the internal usage between C# and C++/CLI will be already resolved, so you won't have to worry about missing dependencies at run time. Well, at least not these dependencies; any you didn't choose to link in will still be handled normally.
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'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
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.
I want to add a VC++ DLL reference into my C# Visual Studio project. But when I try to add it I see, "It is not a valid assembly or COM component".
Please suggest how I can use the VC++ DLL as a reference in a C# project.
There are two options for using a C++ DLL from C#: either COM interop, or P/Invoke. COM Interop involves creating a COM object in your C++ DLL, and then adding it as a reference. You can use the COM object like a C# object (for the most part) at this point.
P/Invoke allows you to call exported functions from C# (think calling standard Win32 API functions from C#). This is likely easier to set up, since all you need to do is export a function, however that could cause you to refactor your code in the C++ DLL, since it's not a very OOP way of doing things.
You can only use C++ components in C# when they have been prepared for use, for example by being written in C++/CLI or being written as a COM server.
If your component is a plain C++ dll you'll need to write some wrapper code, probably best is C++/Cli
I am not sure whether this solve..
run:
tlbimp /out:MyOldCom.dll MyNewAssembly.tlb
Then use it as you would any other assembly.
Please refer
http://msdn.microsoft.com/en-us/library/aa302324.aspx
http://msdn.microsoft.com/en-us/magazine/cc301501.aspx
ie)
One way is to package your DLL as a COM class and Another way is using DllImport