I have an existing program win32 (x86) console app that needs to call managed code (C# from a .Net .dll
). The .dll
is not exposed to COM, but can be called from a C#/WinRT Component and referenced by C /WinRT Console Template app, BUT I can't seem to call it from a win32 x86 console app even after installing the C /WinRT NuGet package. I've built and ran
Following Simon's reply, I was able to create a C# WinRT component that can be called from a Win32 console app. This C# WinRT component DOES output a .dll as well as .winmd. I followed a bit closer to the article Simon posted about consuming with C and managed to get it to work with basic C# functions.
CodePudding user response:
REGDB_E_CLASSNOTREG
means the class that you ask for (whatever it is COM/WinRT etc.) is not registered/known to the activation system (hosted in combase.dll).
The problem probably comes from the fact you're trying to use a registration-free WinRT component.
Let's take this sample as a start for the C# component: Walkthrough: Create a C#/WinRT component and consume it from C /WinRT. So, just create the C# component but don't create the C /WinRT app. (I use Visual Studio 2019 and net5.0-windows10.0.19041.0).
Note: C#/WinRT does produce a .dll (here SampleComponent.dll
), not only metadata.
If you don't build the C /WinRT app, you still need to build a regular .h file to use the C# component. C /WinRT does that for you, but since we don't use this tool, we must build it ourselves. For that, we need two other tools winmdidl.exe
and midlrt.exe
that you'll find from Developer Command Prompt for Visual Studio..See also
How to: Use winmdidl.exe and midlrt.exe to create .h files from windows metadata
So from the SampleComponent.winmd
that you have if you followed the tutorial, run:
winmdidl SampleComponent.winmd
this will create a SampleComponent.idl
file. Now run:
midlrt SampleComponent.idl /metadata_dir "C:\Windows\System32\WinMetadata"
this will create multiple files (proxy, stub, etc.), but we only need SampleComponent.h
. Now, create a standard C console app like this (I don't use C /WinRT I still use Wrl
to simplify my code, but this is not mandatory):
#include <windows.h>
#include <stdio.h>
#include <wrl.h>
#include <wrl/wrappers/corewrappers.h>
#include "path to SampleComponent.h"
#pragma comment(lib, "runtimeobject.lib")
using namespace Microsoft::WRL; // ComPtr
using namespace Microsoft::WRL::Wrappers; // RoInitializeWrapper, HStringReference, HString
using namespace Windows::Foundation; // GetActivationFactory, ActivateInstance
int main()
{
RoInitializeWrapper init(RO_INIT_MULTITHREADED);
HRESULT hr = init;
// all error checks on hr omitted
ComPtr<SampleComponent::IExampleClass> cls;
hr = ActivateInstance(HStringReference(RuntimeClass_SampleComponent_Example).Get(), &cls);
hr = cls->put_SampleProperty(42);
INT32 i;
hr = cls->get_SampleProperty(&i);
wprintf(L"%u\n", i);
ComPtr<SampleComponent::IExampleStatic> clsStatic;
hr = GetActivationFactory(HStringReference(RuntimeClass_SampleComponent_Example).Get(), &clsStatic);
HString str;
hr = clsStatic->SayHello(str.GetAddressOf());
wprintf(L"%s\n", str.GetRawBuffer(nullptr));
}
RuntimeClass_SampleComponent_Example
is from SampleComponent.h
and should be defined like this:
extern const __declspec(selectany) _Null_terminated_ WCHAR RuntimeClass_SampleComponent_Example[] = L"SampleComponent.Example";
If you compile that and run, hr will be REGDB_E_CLASSNOTREG
because the system cannot find the 'SampleComponent.Example'
component.
So what you must do is explained here: How Registration-free WinRT Works
You must add a file to the project with the .manifest
extension (any name should work with recent versions of Visual Studio), for example like this:
<?xml version="1.0" encoding="utf-8"?>
<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
<assemblyIdentity version="1.0.0.0" name="CppConsoleApp"/>
<file name="WinRT.Host.dll">
<activatableClass
name="SampleComponent.Example"
threadingModel="both"
xmlns="urn:schemas-microsoft-com:winrt.v1" />
</file>
</assembly>
assemblyIdentity
's name
is not super important, what is super important is file
and activatableClass
's name
: it must be the same as the host dll name (here it must be WinRT.Host.dll
which is provided by C#/WinRT) and class name you're trying to activate (corresponding to RuntimeClass_SampleComponent_Example
).
You must also copy all the C#/WinRT files mess needed aside your .exe file. That would be : SampleComponent.dll
, Microsoft.Windows.SDK.NET.dll
, WinRT.Host.dll
, WinRT.Host.runtimeconfig.json
, WinRT.Host.Shim.dll
, WinRT.Runtime.dll
.
Note you can use C /WinRT to help building WinRT.Host.runtimeconfig.json
.
And now, it should work.