C#

using Nethereum.Web3;
using Nethereum.Web3.Accounts;
using Nethereum.Util;
using Nethereum.Hex.HexTypes;
 
public class EthereumService
{
    private readonly Web3 _web3;
 
    public EthereumService(string url)
    {
        _web3 = new Web3(url);
    }
 
    public async Task<decimal> GetBalanceAsync(string address)
    {
        var balance = await _web3.Eth.GetBalance.SendRequestAsync(address);
        return Web3.Convert.FromWei(balance.Value);
    }
 
    public async Task<string> SendTransactionAsync(
        string privateKey,
        string toAddress,
        decimal etherAmount)
    {
        var account = new Account(privateKey);
        var web3 = new Web3(account, _web3.Client.Url);
 
        var transaction = await web3.Eth.GetEtherTransferService()
            .TransferEtherAsync(toAddress, etherAmount);
 
        return transaction;
    }
}

public class SmartContractService
{
    private readonly Web3 _web3;
    private readonly Contract _contract;
 
    public SmartContractService(string url, string contractAddress, string abi)
    {
        _web3 = new Web3(url);
        _contract = _web3.Eth.GetContract(abi, contractAddress);
    }
 
    public async Task<T> CallFunctionAsync<T>(string functionName, params object[] parameters)
    {
        var function = _contract.GetFunction(functionName);
        return await function.CallAsync<T>(parameters);
    }
 
    public async Task<string> ExecuteFunctionAsync(
        string functionName,
        string fromAddress,
        params object[] parameters)
    {
        var function = _contract.GetFunction(functionName);
        return await function.SendTransactionAsync(fromAddress, parameters);
    }
}

[ApiController]
[Route("api/[controller]")]
public class EthereumController : ControllerBase
{
    private readonly EthereumService _ethereumService;
 
    public EthereumController(EthereumService ethereumService)
    {
        _ethereumService = ethereumService;
    }
 
    [HttpGet("balance/{address}")]
    public async Task<ActionResult<decimal>> GetBalance(string address)
    {
        try
        {
            var balance = await _ethereumService.GetBalanceAsync(address);
            return Ok(balance);
        }
        catch (Exception ex)
        {
            return BadRequest(ex.Message);
        }
    }
}

public class EventMonitorService
{
    private readonly Web3 _web3;
 
    public async Task MonitorEventsAsync(string contractAddress, string eventName)
    {
        var filterAll = _web3.Eth.GetEvent<YourEventDTO>(contractAddress)
            .CreateFilterInput();
 
        var subscription = _web3.Eth.GetEvent<YourEventDTO>(contractAddress)
            .GetFilterChanges(filterAll);
 
        subscription.Subscribe(evt =>
        {
            Console.WriteLine($"New event: {evt.Event}");
        });
    }
}

public class EthereumUnityManager : MonoBehaviour
{
    private Web3 _web3;
 
    private async void Start()
    {
        _web3 = new Web3("https://polygon.therpc.io/YOUR_API_KEY");
        await InitializeWalletAsync();
    }
 
    private async Task InitializeWalletAsync()
    {
        try
        {
            var balance = await _web3.Eth.GetBalance.SendRequestAsync("YOUR_ADDRESS");
            Debug.Log($"Wallet Balance: {Web3.Convert.FromWei(balance.Value)} MATIC");
        }
        catch (Exception ex)
        {
            Debug.LogError($"Failed to initialize wallet: {ex.Message}");
        }
    }
}