Registration-Free COM from ASP.NET? - asp.net

Question

Windows allows use of a COM object without having to register the COM dll.
The mechanism is to include a "dependent assembly" in the application's manifest:
MyProgram.exe.manifest
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
<assemblyIdentity type="win32" name="myapp.exe" version="1.2.3.4" />
<dependency>
<dependentAssembly>
<assemblyIdentity type="win32" name="Contoso.Frobber" version="5.1.81.4" />
</dependentAssembly>
</dependency>
</assembly>
And then your folder contains:
MyProgram.exe
MyProgram.exe.manifest (if you're using an external manifest; could also be embedded at RT_MANIFEST resource)
Contoso.Frobber.manifest (the COM DLL manifest)
confrob.dll (the dll containing the COM classes we want to use)
with the COM dll's assembly manifest containing:
Contoso.Frobber.manifest
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
<assemblyIdentity type="win32" name="Contoso.Frobber" version="1.0.0.0" />
<file name = "confrob.dll">
<comClass
progid="Frobber.Gizmo"
clsid="{00028C00-0000-0000-0000-000000000046}"
description="Gizmo Frobber by Contoso"
threadingModel = "Apartment" />
<typelib
tlbid="{00028C01-0000-0000-0000-000000000046}"
version="1.0"
helpdir=""/>
</file>
</assembly>
Excellent. i can now use a COM object from a (native or .NET) executable without having to register the COM object.
Now i want to use a COM object from an ASP.NET web-site, without registering the COM object.
Possible?
Bonus Chatter
Windows also allows an exe to call a .NET library, without having to install the .NET assembly into the Global Assembly Cache.

Answer 1

Although I can't test it right now I am pretty sure that this works:
IF the manifest for a DLL is external it will usually be ignored when the DLL is loaded via LoadLibrary (according to MSDN). IF the manifest is embedded into the DLL it is usually honored.
Embed the manifest into the ASP.NET application (i.e. code-behind DLL) - for some ways on how to do this see here and here and here.
UPDATE - as per comments:
The above is a workaround as there is no general way to do this (isolation), at least the ASP.NET creators haven't intended this to be possible - for example the above workaround won't work in cases where the application does not compile to a DLL...

Answer 2

Recently we were handling a similar case that we needed to enable Side by Side COM(reg-free COM) in IIS hosted ASP.NET core application, and we made it like:
embed the manifest to an assembly(.dll)
use CreateActCtx() to activate the manifest.
This approach works fine and it's recommended by MS .NET Runtime Interop Team.