How to adapt Action<string> into FSharpFunc<string, unit>

Question

Attempts to pass an Action to F# code is producing the following syntax error in .net 4.6.1, VS2015...

Error   CS1503  Argument 1: 
cannot convert from 'System.Action<string>' to 
'Microsoft.FSharp.Core.FSharpFunc<string, Microsoft.FSharp.Core.Unit>'

The attempts are as follows...

using Microsoft.FSharp.Core;

....

Action<string> logger = Console.WriteLine;

App.perform(new Action<string>(Console.WriteLine), args);

App.perform(logger, args);

App.perform(new Action<string>(msg => Console.WriteLine(msg)), args);

App.perform((new Action<string>(msg => Console.WriteLine(msg))), args);

App.perform((new Func<string,Unit>(msg => Console.WriteLine(msg))), args);

App.perform(new Func<string,Unit>(Console.WriteLine), args);

What is the proper way to pass System.Console.WriteLine from C# to F#?

Answer 1

Microsoft.FSharp.Core.FuncConvert提供了各种转换/适配器功能，它们中的一个可以适应Action<string>到FSharpFunc<string, unit>。

// Reference: FSharp.Core.dll
var writeLine = Microsoft.FSharp.Core.FuncConvert.FromAction<string>(Console.WriteLine);
App.perform (writeLine);

问题在于，就运行时而言，Action<string>委托和FSharpFunc<string, unit>类是无关的，尽管我们知道它们在概念上很接近。不幸的是，C# 没有添加任何支持来帮助 F# 互操作性。