I need to import a dll made in c# from c++
All the examples I found import a single function from a dll, but as far as I know, you cannot export a single function from c# without exporting the whole class (I'm a bit of a c# newbie though)
I am using node gyp to compile it (I'm building a node module for my web app using v8)
Here is my c# code:
using System;
using System.IO;
using System.Runtime.InteropServices;
[ComVisible(true)]
public class Hello
{
public static void Main()
{
Console.WriteLine("Hello World!");
string createText = "Hello World" + Environment.NewLine;
File.WriteAllText(".\\asd.txt", createText);
}
}
And this is my c++ header file:
#ifndef ASDLIB_H
#define ASDLIB_H
#define ASD_IMPORT __declspec(dllimport)
#define STDCALL __stdcall
class ASD_IMPORT Hello{
public:
STDCALL static void ASD_IMPORT Main();
};
#endif // ASDLIB_H
I normally do this kind of stuff by creating a static C++ CLR Wrapper Lib.
These are the steps I'm normally using (although I don't use it very often):
Here minimal example with using Visual Studio:
1. Create managed C# .NET library Project
Let name it HelloLibManaged
with one file Hello.cs and following content:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace HelloLibManaged
{
public class Hello
{
public void Print()
{
System.Console.WriteLine("Hello from Managed Lib");
}
}
}
Build this lib with x86 or x64 , just dont Any CPU
2. Create a new C++ CLR static lib project within same solution.
Let's name it HelloLibCpp
Add a reference to HelloLibManaged project via Project->Add Reference
Remove automatic created existing .h/.cpp files from Project, and create these 2 files:
HelloUnmanaged.h
#pragma once
namespace hello_managed {
class Hello
{
public:
void Print();
};
}
and
HelloUnmanaged.cpp:
#include "HelloUnmanaged.h"
namespace hello_managed
{
void Hello::Print()
{
HelloLibManaged::Hello^ hello = gcnew HelloLibManaged::Hello();
hello->Print();
}
}
Und Project Properties -> General specify static lib.
In the Build settings specify x86 / x64 - use the same build type as building Managed lib from Step 1.
Now you can build the dll and use it in your other unmanaged C++ projects.
For more advanced stuff, like return types and methods with parameters you have to do Type-Marshalling between managed/unmanaged code. There are many resources online with more information about Type-Conversion between managed/unmanaged code. Keyword: Marshaling.
Related
I am working on WP8 project that includes class library project as C# source code and Windows Runtime Component as C++ source code. Does anyone know whether or not it is possible to create such C# class library which would reference Windows Runtime Component? The ultimate result should be .NET assembly and .WIMND/.DLL runtime component that can be used for application. Currently I cannot build class library because it doesn't see Windows Runtime Component, even though I added it to the project.
More specific. I have, say, MyNs.MyClass.MyMethod() which is defined in C++ runtime component and used from C# class library. Currently I cannot compile C# due to missing method although I have windows runtime component project attached to the same solution.
Although I am butting in because this is not my area, I tried Googling for "c# call windows runtime component". There seem to be many hits/examples, e.g. the first one is https://msdn.microsoft.com/en-us/library/hh755833.aspx.
Does that not help you?
I solved this by adding reference to Windows runtime component manually into the C# class library .csproj file as follows
...
<ItemGroup>
<Reference Include="WindowsRuntimeComponent.winmd" />
</ItemGroup>
...
I managed to make a C++ WRL project and use a class in that project from a C# project by adding a reference in the normal way. The Wrl project (not C++/CX, which also works) was made using some WRL template that I found somewhere on the web. The wrl project required me to make a .idl to define the interface, and produced its .dll and .winmd. Here is some code for those who are battling with this type of thing:
The Wrl class:
#include "pch.h"
#include "WrlTestClass2_h.h"
#include <wrl.h>
using namespace Microsoft::WRL;
using namespace Windows::Foundation;
namespace ABI
{
namespace WrlTestClass2
{
class WinRTClass: public RuntimeClass<IWinRTClass>
{
InspectableClass(RuntimeClass_WrlTestClass2_WinRTClass, BaseTrust)
public:
WinRTClass()
{
}
// http://msdn.microsoft.com/en-us/library/jj155856.aspx
// Walkthrough: Creating a Basic Windows Runtime Component Using WRL
HRESULT __stdcall Add(_In_ int a, _In_ int b, _Out_ int* value)
{
if (value == nullptr)
{
return E_POINTER;
}
*value = a + b;
return S_OK;
}
};
ActivatableClass(WinRTClass);
}
}
The C# code that uses this class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.VisualStudio.TestPlatform.UnitTestFramework;
namespace CSharpClientToWrl
{
[TestClass]
public class UnitTest1
{
[TestMethod]
public void TestMethod1()
{
WrlTestClass2.WinRTClass _winRtTestClass = new WrlTestClass2.WinRTClass();
int _answer = _winRtTestClass.Add(4, 6);
Assert.AreEqual(_answer, 10);
}
}
}
The .idl file of the wrl project:
import "inspectable.idl"; import "Windows.Foundation.idl";
#define COMPONENT_VERSION 1.0
namespace WrlTestClass2 {
interface IWinRTClass;
runtimeclass WinRTClass;
[uuid(0be9429f-2c7a-40e8-bb0a-85bcb1749367), version(COMPONENT_VERSION)]
interface IWinRTClass : IInspectable
{ // http://msdn.microsoft.com/en-us/library/jj155856.aspx // Walkthrough: Creating a Basic Windows Runtime Component Using WRL HRESULT Add([in] int a, [in] int b, [out, retval] int* value);
}
[version(COMPONENT_VERSION), activatable(COMPONENT_VERSION)]
runtimeclass WinRTClass
{
[default] interface IWinRTClass;
} }
How does an unmanaged c++ .dll know where the location of a managed c# .dll is?
Some context:
I have a c++ .dll that imports a type library (.tlb) and inside one of the c++ functions, I instantiate a pointer to the functions inside the c# .dll. Then, using that pointer, I can call the c# functions in c++. I would like to know how c++ .dll know where the c# .dll is? Further, is there a better way to do this type of coding?
Does the .tlb need to be in the same directory as the c# .dll?
One way to accomplishing the above is to register the C# dll file with the Microsoft Windows Registry using the regasm command. This command EXE is included with distributions of Visual Studios. An example use of the command follows:
regasm NameofC#DLL.dll /tlb:NameofC#DLL.tlb
Once you have registered it in the registry you will need to install it to the global assembly cache (GAC) using the gacutil command. This is also included with distributions of Visual Studios. An example use of the command follows:
gacutil /i NameofC#DLL.dll
Once these steps are completed your C++ code will be able to find the C# dll assuming your DLL files are constructed similar to the following:
[C#]
using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace MyNameSpace
{
/// <summary>
/// Interface for C++ DLL. This exposes the functions used inside the dll
/// Make sure the return types, function names, and argument types match the class
/// </summary>
[ComVisible(true)]
[Guid("CBA208F2-E43B-4958-97C7-C24EA5A213DE")]
public interface IMyClass
{
int Function1();
int Function2();
}
[ClassInterface(ClassInterfaceType.None)]
[Guid("579091E6-83A1-4aa5-89A7-F432AB2A57E3")]
[ComVisible(true)]
public class MyClass : IMyClass
{
public MyClass()
{
//Constructor
}
public int Function1()
{
//Do something in C#
return an integer;
}
public int Function2()
{
//Do something else in C#
return an integer;
}
}//End Class MyClass
}//End namespace MyNameSpace
Everywhere you see a GUID being used, that is a randomly generated global identifier used to identify your C# code. This number can be randomly generated using the GUID creation tool provided with Visual Studios under the "Tool menu" and the "Create GUID" option. Select Registry format and press "New GUID". Then just press copy and paste it where the GUID needs to be (Remove the brackets!)
[C++]
#include <windows.h>
#include "stdafx.h"
#include <cstdlib>
#pragma warning (disable: 4278)
#import <mscorlib.tlb> raw_interfaces_only
#include <stdio.h>
//This path needs to be valid at compile time. The file does not need to be there in runtime when using the DLL after compile.
#import "C:\\...\\NameofC#DLL.tlb" no_namespace named_guids
extern "C" _declspec(dllexport) int _Function1()
{
int result = 0;
IMyClass *CSharpInterface = NULL;
//Open interface to C#
CoInitialize(NULL);
HRESULT hr = CoCreateInstance(CLSID_MyClass, NULL, CLSCTX_INPROC_SERVER,
IID_IMyClass, reinterpret_cast<void**>(&CSharpInterface));
//Call Function1 C# method
result = CSharpInterface->Function1();
//Close interface
CoUninitialize();
//Return result
return result;
}
The required TLB file at compile time can be generated using the tlbexp command also included with visual studios.An example use of the command follows:
tlbexp NameofC#DLL.dll
If you do not specify a path it will default to the following path:
C:\Program Files\Microsoft Visual Studio 9.0\VC
There a several places you can mess this up and the C# DLL call will fail.
Regards,
SeaMossDesign
Maybe I'm missing something, but you can create a custom CLR host and invoke a method from C# without pointer. Check ICLRRuntimeHost::ExecuteInDefaultAppDomain out.
I am trying to call my C++ library from my C# application (via C++/CLI). I followed the example from this question (for my specific application). The setup of my application is:
Project1: C++ Project (I compile this to a DLL)
Project2: C++ Project (my CLR wrapper; just the header file per the example above; references Project1)
Project3: C# Project (references Project2)
Unfortunately, when I actually go to access the CLR wrapper object in my C# application, I receive the following error:
The type or namespace name 'YourClass'
could not be found (are you missing a
using directive or an assembly
reference?)
Do I have the project setup incorrectly, or is there something else I should be looking into? (Unfortunately, I cannot post the code for proprietary reasons, but it is a very simple bit of code and easily follows the above example.)
Update:
So I did exactly what Chris said to do (see answer below), but I am still receiving a message from my C# application that "The type or namespace name 'MyProgram' could not be found (are you missing a using directive or an assembly reference?). Here is a (mock-up) of my code.
Project1 - This is my C++ application. It compiles/works. I have used it elsewhere. (I get a DLL out of this build.)
Project2 - Here is my code for my wrapper.
MyWrapper.h
#pragma once
#include "myorigapp.h"
using namespace System;
namespace MyProgram
{
public ref class MyWrapper
{
private:
myorigapp* NativePtr;
public:
MyWrapper()
{
NativePtr = new myorigapp();
}
~MyWrapper()
{
delete NativePtr;
NativePtr = NULL;
}
void dostuff()
{
NativePtr->dostuff();
}
}
}
Project3 - This is my C# application.
Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MyProgram;
namespace Testing
{
class Program
{
static void Main(string[] args)
{
MyWrapper p = new MyWrapper();
p.dostuff();
}
}
}
Project3 references Project2 which references Project1. Everything builds without errors (except the error I described above in the C# code on the using MyProgram line).
Just including the header from a pure C++ application isn't good enough. You need to wrap your unmanaged objects with managed ones in Project2 (i.e. public ref class YourClassDotNet)
#include "YourHeader.h"
namespace MyManagedWrapper
{
public ref class YourClassDotNet
{
private:
YourClass* ptr;
public:
YourClassDotNet()
{
ptr = new YourClass();
}
~YourClassDotNet()
{
this->!YourClassDotNet();
}
!YourClassDotNet()
{
delete ptr;
ptr = NULL;
}
void SomeMethod()
{
ptr->SomeMethod();
}
}
}
Okay, well, I now feel dumb.
It turns out that the problem I was having (which I solved a couple weeks ago - just got around to updating this answer) was that I had included the header file (see Chris' answer for that), but I hadn't actually included the CPP file (which is empty other than including the header file).
Once I did this, the DLL compiled correctly and I could call the C++ functions (using C++/CLI) from my C# code.
Chris showed you the way to create a managed class that uses unmanaged code inside. There is a lot of that that you can do in C# using unsafe (it's just that hardly anyone does).
However, the reverse is also possible: using .NET types directly from a native type/function.
The thing to watch out for is that any managed pointer has to be marked as such. For this purpose, C++/CLI defines a special type of smartpointer gcroot<T> (mimicking boost::shared_pointer or std::auto_ptr in a way). So to store a managed string inside your C++ class, use the following:
#include <string>
#include <vcclr.h>
using namespace System;
class CppClass {
public:
gcroot<String^> str; // can use str as if it were String^
CppClass(const std::string& text) : str(gcnew String(text.c_str())) {}
};
int main() {
CppClass c("hello");
c.str = gcnew String("bye");
Console::WriteLine( c.str ); // no cast required
}
Note that (if it hasn't been fixed these days) you'll run into a bit of friction with the mismatch between managed null and C/C++ NULL.
You can't easily type, as you would expect:
gcroot<Object^> the_thing;
...
if (the_thing != nullptr)
...
}
Instead you'd have to use the native style (the smart wrapper gcroot handles this)
gcroot< Object^ > the_thing;
if ( the_thing != NULL ) {} // or equivalently...
if ( the_thing ) {}
// not too sure anymore, but I thought the following is also possible:
if ( the_thing != gcroot<Object>(nullptr) ) {}
Note: I don't have access to a windows machine anywhere near these days, so I've quoted from memory
I've been working with trying to link up some c++ code and wrap it inside a COM object to access via C#. I created an atl project and added a simple method such as Add(double a, double b). The following is the code from my atl.h file:
// atl.h : Declaration of the Catl
#pragma once
#include "resource.h" // main symbols
#include "com_i.h"
#if defined(_WIN32_WCE) && !defined(_CE_DCOM) && !defined(_CE_ALLOW_SINGLE_THREADED_OBJECTS_IN_MTA)
#error "Single-threaded COM objects are not properly supported on Windows CE platform, such as the Windows Mobile platforms that do not include full DCOM support. Define _CE_ALLOW_SINGLE_THREADED_OBJECTS_IN_MTA to force ATL to support creating single-thread COM object's and allow use of it's single-threaded COM object implementations. The threading model in your rgs file was set to 'Free' as that is the only threading model supported in non DCOM Windows CE platforms."
#endif
// Catl
class ATL_NO_VTABLE Catl :
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<Catl, &CLSID_atl>,
public Iatl
{
public:
Catl()
{
}
DECLARE_REGISTRY_RESOURCEID(IDR_ATL)
DECLARE_NOT_AGGREGATABLE(Catl)
BEGIN_COM_MAP(Catl)
COM_INTERFACE_ENTRY(Iatl)
END_COM_MAP()
DECLARE_PROTECT_FINAL_CONSTRUCT()
HRESULT FinalConstruct()
{
return S_OK;
}
void FinalRelease()
{
}
public:
STDMETHOD(Add)(DOUBLE a, DOUBLE b);
};
OBJECT_ENTRY_AUTO(__uuidof(atl), Catl)
The following is from the atl.cpp file
// atl.cpp : Implementation of Catl
#include "stdafx.h"
#include "atl.h"
STDMETHODIMP Catl::Add(DOUBLE a, DOUBLE b)
{
// TODO: Add your implementation code here
return a + b;
}
Inside my c# file I'm calling the dll... after i referenced it... it sees the dll but not the methods assigned. which is my problem. Heres the code from program.cs
sing System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
namespace sharpdll
{
class Program
{
[DllImport("com.dll")]
public static extern double Add(double a, double b);
static void Main(string[] args)
{
Add(2, 3);
}
}
}
Debugging breaks at Add(2, 3);
Says "Unable to find an entry point named 'Add' in DLL 'com.dll'."
Any ideas?
DllImport is for PInvoke (to native Win32 dlls).
You want COM Interop.
Register your ATL com object, then Add a reference to it, as you would to any .Net or COM component.
An alternative to ATL, you can expose your C++ functionality through C++/CLI.
Hope this helps,
i'm converting C++ to C++/CLI and would like to expose some managed classes as COM objects. In C# it was easy and setting [ComVisible] & inheriting from interface (also ComVisible) did the job.
However C++ project build as C++/CLI does not export DllRegisterServer.
Here is sample project (started from CLR Console Application project in VS 2008).
#include "stdafx.h"
using namespace System;
using namespace System::Runtime::InteropServices;
[ComVisible(true)]
[Guid("E3CF8A18-E4A0-4bc3-894E-E9C8648DC1F0")]
[InterfaceType(ComInterfaceType::InterfaceIsDual)]
public interface class ITestInterface
{
void TestMethod();
};
[ComVisible(true)]
[Guid("1514adf6-7cb0-4561-9fbb-b75c0467149b")]
public ref class CliComClass : ITestInterface
{
public:
virtual void TestMethod()
{
}
};
int main(array<System::String ^> ^args)
{
Console::WriteLine(L"Hello World");
return 0;
}
When I run regsvr32 on output .exe I got error saying DllRegisterServer was not found. I've tried google for some help but with no success.
You need to use TlbExp instead, TlbExp is the tool use to export managed classes to COM, it will read the assembly find the ComVisible type and register them.