Why do I get System.NullReferenceException in my c# script while my executable of the same code is working?

Question

I have the following .csx script:

#r "C:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.Management\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Management.dll"
using System.Management;
ManagementClass cls = new ManagementClass("\\\\.\\root\\default:StdRegProv");

When I run this using dotnet script I get this error:

System.NullReferenceException: Object reference not set to an instance of an object.
    at System.Management.MTAHelper.IsNoContextMTA()
    at System.Management.MTAHelper.CreateInMTA(Type type)
    at System.Management.ManagementPath.CreateWbemPath(String path)
    at System.Management.ManagementPath..ctor(String path)
    at System.Management.ManagementClass..ctor(String path)
    at Submission#0.<<Initialize>>d__0.MoveNext() in <..path..>\script.csx:line 3
 --- End of stack trace from previous location ---
    at Dotnet.Script.Core.ScriptRunner.Execute[TReturn](String dllPath, IEnumerable`1 commandLineArgs) in <...path...>\Temp\tmpBFB\Dotnet.Script.Core\ScriptRunner.cs:line 110

If I compile the following code in visual studio, everything works fine:

using System.Management;
class Script {
    static void Main() {
        ManagementClass cls = new ManagementClass("\\\\.\\root\\default:StdRegProv");
    }
}

Why ? How can I get my .csx script to work ?

Answer 1

dotnet script runs off .NET Core and I don't think WMI works in .NET Core as it needs COM interop. See this.

Also, global runtime dll for .NET CORE is not in GAC but rather in a runtime package store.