How to call F# type extensions (static member functions) from C#

Question

FSharp code is structured as following (I'm not in control of the source).

namespace FS

[<AbstractClass; Sealed>]
type TestType() = 
    static member IrrelevantFunction() = 
        0

[<AutoOpen>]
module Extensions = 
    type TestType with
        //How do we call this from C#
        static member NeedToCallThis() = 
            0

module Caller = 
    let CallIt() = 
        //F# can call it
        TestType.NeedToCallThis()

C# calling code is as follows

public void Caller()
{
    TestType.IrrelevantFunction();

    //We want to call this
    //TestType.NeedToCallThis();

    //Metadata:

    //namespace FS
    //{
    //    [Microsoft.FSharp.Core.AutoOpenAttribute]
    //    [Microsoft.FSharp.Core.CompilationMappingAttribute]
    //    public static class Extensions
    //    {
    //        public static int TestType.NeedToCallThis.Static();
    //    }
    //}

    //None of these compile
    //TestType.NeedToCallThis();
    //Extensions.TestType.NeedToCallThis.Static();
    //Extensions.TestType.NeedToCallThis();
}

Answer 1

I don't believe the method can be called directly from C# without using reflection, as the compiled method name is not a valid method name in C#.

Using reflection, you can call it via:

var result = typeof(FS.Extensions).GetMethod("TestType.NeedToCallThis.Static").Invoke(null,null);