Failover Func

FailoverFunc.cs

using System;
using System.Linq;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace Jason.Tests {
    [TestClass]
    public class TryParseTests {
        [TestMethod]
        public void TestTryParse_Func_Bad() {
            Assert.AreEqual(0, "s".TryParse(Failover<int>));
        }
        [TestMethod]
        public void TestTryParse_Func_Zero() {
            Assert.AreEqual(0, "0".TryParse(Failover<int>));
        }
        [TestMethod]
        public void TestTryParse_Func_Five() {
            Assert.AreEqual(5, "5".TryParse(Failover<int>));
        }

        public T Failover<T>(string input) {
            // try to recover from failed parse here
            Console.WriteLine("Did our extra failure work here");
            return default(T);
        }
    }

    public static class Helpers {
        // adapted from skoon https://gist.github.com/963991
        public static duck TryParse<duck>(this string stringToParse, Func<string,duck> failover) {
            if (typeof(duck).HasMethod("TryParse")) {
                var m = typeof(duck).GetMethod("TryParse", new Type[] { typeof(string), typeof(duck).MakeByRefType() });
                duck outParam = Activator.CreateInstance<duck>();
                object[] ps = new object[] { stringToParse, outParam };
                bool result = (bool)m.Invoke(null, ps);
                if (result)
                    return (duck)ps[1];
            }
            return failover(stringToParse);
        }
        private static bool HasMethod(this Type type, string methodName) {
            var m = type.GetMethods();
            return (m.Any(x => x.Name == methodName));
        }
    }
}