.NET Framework 4.8.1 - Failed to resolve assembly: netstandard, Version=2.0.0.0

[fandrei]

            var resolver = new DefaultAssemblyResolver();
            var asm = resolver.Resolve(new AssemblyNameReference("netstandard", new Version("2.0")));
            var module = asm.MainModule;

This code successfully resolves the assembly when executed from a .NET 6 app, but it fails in a .NET 4.8.1 app:

Failed to resolve assembly: 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null'

[pengweiqhca]

Missing PublicKeyToken.

[fandrei]

@pengweiqhca that doesn't matter.

[lextm]

DefaultAssemblyResolver is not able to resolve many assemblies if you check its source code (and BaseAssemblyResolver). You need to add search directories to guide it.

You might read https://github.com/jbevain/cecil/discussions/802 to study a similar case.