将FSharpFun从C＃传递到F＃

Question

F# Definition of a function in a module.

module ClassLibrary1.Functions

let checkThis item f =
    if f item then
        printfn "HIT"
    else
        printfn "MISS"

f# unit tests - works

[<TestMethod>]
    member this.TestFunctions() =
        checkThis 5 (fun x -> x > 3)

in c# unit test

using ClassLibrary1;

namespace TestProject
{
    [TestClass]
    public class UnitTest1
    {

        [TestMethod]
        public void TestFunctions()
        {
            FSharpFunc<int, bool> s = x => x > 3 // error, how to declare?
            Functions.checkThis(5, s);
        }
     }
}

Error

Cannot conver initializer type "lambda expression" to target type

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Edit

Screenshots to help the answer.

Screenshot 3

Answer 1

For the lastest F# version (10.2.3), use

var s = FuncConvert.FromFunc(new Func<int, bool>(x => x > 3));

With FX_NO_CONVERTER defined:

FSharpFunc<int, bool> s = new Converter<int, bool>(x => x > 3); 
var s = FSharpFunc<int, bool>.FromConverter(x => x > 3);
var s = FuncConvert.ToFSharpFunc(new Converter<int, bool>(x => x > 3));