Callback from C# to F#

Question

I have an F# class library as such:

namespace FsharpTestSystem

open System
open System.IO

open TCLoggerEntity
open TCIQuoteEntity

type TestCallback() = 
    member this.LoggerOutput() = Logger.Info("F#")
    member this.OnQuote(q : TCQuote) = Console.WriteLine(q.ToString())

Adding a reference of this F# assembly into a C# project, I have tested that I can call LoggerOutput fine from C#. However, if I try to have C# event callback execute in F# I get an error on the line below:

From C#:

using FsharpTestSystem;

public delegate void QuoteChangeEvent(TCQuote q);
event QuoteChangeEvent OnQuoteChange;

TestCallback fsts = new TestCallback();
api.MAPI.OnQuoteChange += fsts.OnQuote(); // this doesn't work

fsts.LoggerOutput(); // This works fine

Answer 1

you are invoking your method, which would try and use whatever OnQuote returned as the event handler.

OnQuote is the event handler, so try :-

api.MAPI.OnQuoteChange += fsts.OnQuote;