How to get the Left or Right value of Either<L, R>

[juchom]

Hello,

I plan to introduce a bit of functional programming in a C# project and I want to introduce some simple monads at the beginning.

In this small sample how could I access the value of Left or Right ?

public int MyFunction(int i)
{
    var res = InnerFunction(i);

    if (res.IsLeft) throw new Exception([Left Value]);
    
    var finalRes = [Right Value] + 1;
    return finalRes;
}

private Either<string, int> InnerFunction(int i)
{
    return i % 2 == 0
    ? Left("this is an error");
    : Right(123);
}   

[aloslider]

using LanguageExt;
using static LanguageExt.Prelude;

static int MyFunction(int i) =>
    InnerFunction(i).IfLeft(x => throw new Exception(x));

static Either<string, int> InnerFunction(int i) =>
    i % 2 == 0 // assuming error should be on mod 2?
    ? Left("this is an error")
    : Right(123);