c# - How to get all types in a referenced assembly?

Question

For whatever reason, I can't seem to get the list of types in a referenced assembly. Not only that, I can't even seem to be able to get to this referenced assembly.

I tried AppDomain.CurrentDomain.GetAssemblies(), but it only returns assemblies that have already been loaded into memory.

I tried Assembly.GetExecutingAssembly().GetReferencedAssemblies(), but this just returns mscorlib.

What am I missing?

Answer 1

Note that Assembly.GetReferencedAssemblies only includes a particular assembly if you actually use a type in that assembly in your assembly (or a type that you use depends on a type in that assembly). It is not enough to merely include an assembly in the list of references in Visual Studio. Maybe this explains the difference in output from what you expect? I note that if you're expecting to be able to get all the assemblies that are in the list of references in Visual Studio using reflection that is impossible; the metadata for the assembly does not include any information about assemblies on which the given assembly is not dependent on.

That said, once you've retrieved a list of all the referenced assemblies something like the following should let you enumerate over all the types in those assemblies:

foreach (var assemblyName in Assembly.GetExecutingAssembly().GetReferencedAssemblies()) {
    Assembly assembly = Assembly.Load(assemblyName);
    foreach (var type in assembly.GetTypes()) {
        Console.WriteLine(type.Name);
    }
}

If you need the assemblies that are referenced in Visual Studio then you will have to parse the csproj file. For that, check out the ItemGroup element containing Reference elements.

Finally, if you know where an assembly lives, you can load it using Assembly.LoadFile and then essentially proceed as above to enumerate over the types that live in that loaded assembly.