Registration-Free COM from 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.

@RB The program that wants to depend on an unregistered DLL needs to declare that dependancy in it's manifest (MyProgram.exe.manifest in my original example). In the case of ASP.NET, the program that i would have to manfiest is w3wp.exe, creating w3wp.exe.manifest and place it in Program Files. i shouldn't be manifesting all www worker processes; i only want to manifest my "web-site". And i see no way to "manifest a web-site". — Ian Boyd
I'm not sure what you are trying to do. This is an old DAO-based visual control, so at best you might use it client-side in its unbound mode. Reg-free COM does not apply and isn't required. There is a way to load such an ActiveX control in IE via the <object> tag from a CAB file on your site, as long as you create and specify a license package (LPK) file for the page too. Even this assumes relaxed security in IE though. — Bob77
dbgrid32.ocx was only an example to help people understand what registration-free COM is used for. i will replace dbgrid32.ocx with the filename i'm actually using. It doesn't change the question or the concepts - although might make it more difficult for people to understand what i'm asking. — Ian Boyd
Perhaps you can dig an answer out of this: Isolating ASP .Net 2.0 Applications — Bob77

Yahia Yahia · Accepted Answer · 2012-02-07T21:15:29

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...

Registration-Free COM from ASP.NET?

Bonus Chatter

1 Answers