How can I check if a .Net dll makes use of COM interop services?-CodePudding

Is there a command line tool that tells me whether a given .Net assembly makes use of COM interop services?

Example that does not make use of COM interop:

internal class ServerClass { }

Example that does:

[ComImport]
[Guid("114383E9-1969-47D2-9AA9-91388C961A19")]
internal class ServerClass { }

CodePudding user response：

I suspect the answer is no.

But you could build one. Start with the output of a decompiler and look for use of types and methods unique to COM interop (eg. Type.GetTypeFromProgID).

CodePudding user response：

It seems that class and interfaces imported from COM - and that is all that can be COM imported - can be grepped with a simple regular expression (or what findstr considers a regular expression - note the escaped space, which would otherwise be taken for an "OR" - i.e. a | in most regex languages):

> ildasm /text NetClient.exe | findstr "\.class.*\ import "
.class interface private abstract auto ansi import NetClient.IServer
.class interface private abstract auto ansi import NetClient.Server
.class private auto ansi import beforefieldinit NetClient.ServerClass

I've tested this with a bunch of dlls already and there was no false positive - I only hope there were no false negatives either...

Also - thanks Simon in the comments - CreateInstance() can be used to load dlls dynamically at runtime, so it should be checked as well (using grep this time instead of findstr, due to the latter's unusual and limited regexp syntax):

> ildasm /text file.dll \
| grep -E 'call.*System.Activator|Reflection.Assembly)::CreateInstance'

N.B. ildasm should come installed with Visual Studio, and is easiest to call when using the Visual Studio Developer Command Prompt.