Nethereum contract.getPastEvents equivalent

Question

I want to query all transfers regarding a contract with Nethereum. This means, in the end I want to have all transactions, so that I can print a statement of account.

I suppose with the web3.js library the call would be something like this on the contract:

contract.getPastEvents('Transfer', {fromBlock: 1, toBlock: 'latest'}, callbackFunc)

However, I didn't find a getPastEvents equivalent in Nethereum.

Answer 1

Kevin Small answered this question with this example in a direct conversation in Gitter Nethereum chat:

using System;
using System.Numerics;
using System.Threading.Tasks;
using Nethereum.ABI.FunctionEncoding.Attributes;
using Nethereum.Contracts;
using Nethereum.RPC.Eth.DTOs;
using Nethereum.Web3;

internal class Program
{
    // Define event we want to look for
    // Note: in a visual studio project outside of this playground, you have the option to install nuget package
    // Nethereum.StandardTokenEIP20 and add a using Nethereum.StandardTokenEIP20 to provide class TransferEventDTO,
    // instead of defining it here.
    [Event("Transfer")]
    public class TransferEventDTO : IEventDTO
    {
        [Parameter("address", "_from", 1, true)]
        public string From { get; set; }

        [Parameter("address", "_to", 2, true)]
        public string To { get; set; }

        [Parameter("uint256", "_value", 3, false)]
        public BigInteger Value { get; set; }
    }

    private static async Task Main(string[] args)
    {
        var url = "https://mainnet.infura.io/v3/7238211010344719ad14a89db874158c";
        var web3 = new Web3(url);
        // This is the contract address of the DAI Stablecoin v1.0 ERC20 token on mainnet
        // See https://etherscan.io/address/0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359
        var erc20TokenContractAddress = "0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359";

        var transferEventHandler = web3.Eth.GetEvent<TransferEventDTO>(erc20TokenContractAddress);
        // Just examine a few blocks by specifying start and end blocks
        var filter = transferEventHandler.CreateFilterInput(
            fromBlock: new BlockParameter(8450678),
            toBlock: new BlockParameter(8450698));
        var logs = await transferEventHandler.GetAllChanges(filter);

        Console.WriteLine($"Token Transfer Events for ERC20 Token at Contract Address: {erc20TokenContractAddress}");
        foreach (var logItem in logs)
            Console.WriteLine(
                $"tx:{logItem.Log.TransactionHash} from:{logItem.Event.From} to:{logItem.Event.To} value:{logItem.Event.Value}");
    }
}

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