Try following these steps: Make sure both projects, unmanaged C++ and managed C# have the same bitness, either x86 or x64. Let’s say it’s x86, for clarity. Open Admin Command Prompt and register your COM DLL: C:\Windows\SysWOW64\regsvr32.exe c:\full-path\ComLib.Interop.dll Run Visual Studio as Admin. Do steps 1,2,4,5,6. Don’t do 3. See if you get to 7. … Read more
Calling regasm without administrative rights for COM interop I think it should be possible to use RegistrationServices.RegisterAssembly and RegOverridePredefKey APIs together to implement automatic registration under the HKCU hive, in a UAC-friendly way. I’ve posted a more detailed answer here.
No, it’s not strictly necessary to apply any of these attributes in your own code. They’re all optional, and automatically applied to your code depending on the type of the parameter. Essentially, they have the following C# keyword equivalents: You get [In] by default. The ref keyword gets you [In, Out]. The out keyword gets … Read more
This is going to be a bit long. First of all, thanks Matt Smith and Hans Passant for your ideas, they have been very helpful. The problem was caused by a good old friend, Application.DoEvents, although in a novelty way. Hans has an excellent post about why DoEvents is an evil. Unfortunately, I’m unable to … Read more
“Make assembly COM visible” is a big hammer to make all public types in the assembly [ComVisible]. Rarely desirable, you will want to select the specific types that you want to be visible, like you did in your snippet. After the assembly is built, it needs to be registered so that a COM client can … Read more
When setting Register For Com interop I’ve found that you do need to run as Administrator. Without Administrator trying to compile I got errors like: Cannot register assembly “C:\TFS\Project\Src\ProjectAddin\bin\Debug \ProjectAddin.dll” – access denied. Please make sure you’re running the application as administrator. Access to the registry key ‘HKEY_CLASSES_ROOT\CLSID{3A6192EA-3C9C-39EB-99A3-3DBFF8CA118F}’ is denied. The above registry key didn’t … Read more
I’ve found the following excerpt from Adam Nathan’s “.NET and COM: The Complete Interoperability Guide”: If the COM object lives in an STA, any calls from MTA threads are marshaled appropriately so the COM object remains in its world of thread affinity. But, in the other direction, no such thread or context switch occurs. Thus, … Read more
To add to the already existing answers: with .NET 4.0, it’s actually quite simple to consume a C# dll in your VBA project without registering the COM. EDIT: I just tried this with the mscorlib.tlb and mscoree.tlb that are in C:\windows\Microsoft.NET\Framework\v2.0.50727— loading an assembly compiled in 3.5– and it worked just fine. So apparently you … Read more
My biggest gripe would be the name, T; Add might be more illusrative of the usage. I’d also add where T : class to the generic method, but the “fluent API” seems usable. I’d also be inclined to flatten the code a bit. I can also see some ways of using the Expression API to … Read more
It should be fairly straightforward to get a basic .NET assembly exposed to COM – I’ve never tried the COM Class project template, so this is the way I’ve managed it in the past: Create a new (bog standard) .NET class library using C# or VB. Define a COM interface (replace GUIDs with your own): … Read more