Decode input, checking Function Message before hand.

[juanfranblanco]

using Nethereum.Web3;
using Nethereum.ABI.FunctionEncoding.Attributes;
using Nethereum.Contracts.CQS;
using Nethereum.Util;
using Nethereum.Web3.Accounts;
using Nethereum.Hex.HexConvertors.Extensions;
using Nethereum.Contracts;
using Nethereum.Contracts.Extensions;
using System;
using System.Numerics;
using System.Threading;
using System.Threading.Tasks;

public class GetStartedSmartContracts
{

    [Function("transfer", "bool")]
    public class TransferFunction : FunctionMessage
    {
        [Parameter("address", "_to", 1)]
        public string To { get; set; }

        [Parameter("uint256", "_value", 2)]
        public BigInteger TokenAmount { get; set; }
    }

    ///*** THE MAIN PROGRAM ***
    public static async Task Main()
    {
        var web3 = new Web3("https://mainnet.infura.io/v3/7238211010344719ad14a89db874158c");
        var txn = await web3.Eth.Transactions.GetTransactionByHash.SendRequestAsync("0x0404a0517a7443db1787b5461b9d5fc18546809419c0cc6a736599b60677ed71");
        if(txn.IsTransactionForFunctionMessage<TransferFunction>()){
            var transfer = new TransferFunction().DecodeTransaction(txn);
            Console.WriteLine(Web3.Convert.FromWei(transfer.TokenAmount));
            Console.WriteLine(transfer.To);
        }

    }
}