Can we use void method with MapResult C#

Question

I am trying to use void methods with MapResult method in Main() method in console application. Following is my code, Class1, Class2 and Class3 inherits AbstractClass and implements it's Execute() method:

Parser.Default.ParseArguments<
                        Class1, 
                        Class2,
                        Class3>(command.Split(' '))
                      .MapResult((AbstractClass o) => o.Execute(), err => null);

In the above code, my Execute() method returns void. I receive following error:

The type arguments for method 'ParserResultExtensions.MapResult(ParserResult, Func, Func, TResult>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

However, if I change return type of Execute() method to int, it works fine.

Please suggest me some solution to use void returning method with MapResult.

Answer 1

Assuming you are using CommandLineParser (https://github.com/commandlineparser/commandline), MapResult requires you to provide a return value indicating success/failure. Try this:

.MapResult((AbstractClass o) => {o.Execute(); return 1;}, err => null);