.NET Framework (v 4.0) COM Registration free called from Win32 C++ application

Question

I need to create a registration free COM object in .Net Framework using C#.

I've followed the MSDN walkthrough. I've to work on it because, or it is not enough clear to me, or it is not correct, however this is an old post and I use Visual Studio 2015 on Windows 10, so maybe something is changed.

Here in the following the steps that I've made to make it work:

Compile COM C# dll SideBySide.dll (Target Framework 2.0), of course I've not registered it by regasm.
I don't use the approach described in the tutorial, it seems not work for me. I create SideBySide.Manifest by mt.exe, here's the command:

mt -outputresource:"<path SidebySide.dll>" -manifest "<SideBySide.manifest>"

I've manually modified the generated manifest to remove all not useful tags, and add the mandatory ones. Here is the modified manifest:

<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity
        name="SideBySide"
        version="1.0.0.0"
        type="win32" />
    <clrClass
        clsid="{4B72FC46-C543-4101-80DB-7777848D1357}"
        progid="SideBySide.SideBySideClass"
        threadingModel="Both"
        name="SideBySide.SideBySideClass"
        runtimeVersion="v2.0.50727">
    </clrClass>
    <file name="SideBySide.dll">
    </file>
</assembly>

I've added the manifest to SideBySide.dll with this command:

mt -outputresource:"<Path SidebySide.dll>" -manifest "SideBySide.manifest"
I've exported the TLB from SideBySide.dll using tlbexp`.
I've set No in the configuration Properties -> Manifest tool -> Embed Manifest of the C++ client.

I've compiled client.exe, and then I've applied changes to the client.exe.manifest file. Here is the modified manifest:

<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity
        type = "win32"
        name = "client"
        version = "1.0.0.0" />
    <dependency>
        <dependentAssembly>
            <assemblyIdentity
                type="win32"
                name="SideBySide"
                version="1.0.0.0" />
        </dependentAssembly>
    </dependency>
</assembly>

Everything is working well, and it seems that I can consume the .Net Framework COM interface from the native C++ application.

However, there is an issue when I try to compile SideBySide.dll with .Net Framework 4.0 or newer, when I call CreateInstance:

ISideBySideClassPtr ptr;
HRESULT hr = ptr.CreateInstance(__uuidof(SideBySideClass));

This error occurs:

0x8013101b : This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

Of course, I've tried to perform all the steps listed above, I try also to specify the runtime version in the manifest of the DLL, but it was not useful.

I also read this post. The problem is the same, but the solution, in my opinion, is not suitable for me, because I need to call a C# COM object from a native client.

Is there some workaround to apply, or do I need another approach to my problem?

Sorry for the late response. I hope you have solved your problem. However yes I have solved my problem. In what I've written there is nothing wrong, except the runtime version v2.0.50727 to v4.0.30319. I suggest to write your manifest on your own without using automatic tool ... using the sample i've listed before. I have also a little sample of a console application calling a c# library SxS if you need — Alessandro Ciurlo
Thanks for answering. I haven't suceeded with manifest stuff because native app did not want to load v4.0.30319 of CLR, it apparently loaded a lower version, with which component was incompatible. So, I've found another way to do it without registration and even without manifest, you just need to specify a path to you .net dll: codeproject.com/Articles/1199546/… This approach works quite reliably for all cases I need. — Alex B.

0909EM 0909EM · Accepted Answer · 2017-11-04T00:48:56

I appreciate this a little late, but for anyone else that comes across this...

I had this problem earlier today. My Registration Free COM library is built with .Net 4.5.2, my solution was to use the "runtimeVersion" attribute as follows

<clrClass 
   clsid="{...}" 
   progid="Library.Name" 
   threadingModel="Both" 
   name="Library.Name.Class"
   runtimeVersion="v4.0.30319">

Alternatively, you can leave out the runtimeVersion attribute (or specify v2.0.50272) and compile your library for .Net 3.5. Either solution appears to resolve the issue.

.NET Framework (v 4.0) COM Registration free called from Win32 C++ application

2 Answers