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Query Blocks and Transactions

After sending transactions (as covered in Transfer Ether and Send Transactions), you'll want to inspect what happened on-chain. All queries in this guide are read-only — no gas, signing, or fees needed.

This guide covers querying blocks, looking up transactions by hash, reading receipts to check success/failure, and detecting whether an address is a contract or a regular account.

dotnet add package Nethereum.Web3

Connect to Ethereum​

using Nethereum.Web3;

var web3 = new Web3("https://mainnet.infura.io/v3/YOUR-PROJECT-ID");

Get the Current Block Number​

var blockNumber = await web3.Eth.Blocks.GetBlockNumber.SendRequestAsync();
Console.WriteLine("Current block number: " + blockNumber.Value);

Get a Block with Its Transactions​

Use GetBlockWithTransactionsByNumber to retrieve a block with full transaction objects:

using Nethereum.Hex.HexTypes;

var block = await web3.Eth.Blocks.GetBlockWithTransactionsByNumber
    .SendRequestAsync(new HexBigInteger(8257129));

Console.WriteLine("Block number: " + block.Number.Value);
Console.WriteLine("Block hash: " + block.BlockHash);
Console.WriteLine("Number of transactions: " + block.Transactions.Length);

// Access individual transactions
Console.WriteLine("Transaction 0 From: " + block.Transactions[0].From);
Console.WriteLine("Transaction 0 To: " + block.Transactions[0].To);
Console.WriteLine("Transaction 0 Value: " + block.Transactions[0].Value);
Console.WriteLine("Transaction 0 Hash: " + block.Transactions[0].TransactionHash);

Use GetBlockWithTransactionsHashesByNumber if you only need transaction hashes (lighter response).

Get a Block by Hash​

var block = await web3.Eth.Blocks.GetBlockWithTransactionsByHash
    .SendRequestAsync("0xabc123...");

Get a Transaction by Hash​

var transaction = await web3.Eth.Transactions.GetTransactionByHash
    .SendRequestAsync(
        "0xb4729a0d8dd30e3070d0cb203090f2b792e029f6fa4629e96d2ebc1de13cb5c4");

Console.WriteLine("From: " + transaction.From);
Console.WriteLine("To: " + transaction.To);
Console.WriteLine("Value: " + transaction.Value);
Console.WriteLine("Hash: " + transaction.TransactionHash);

For EIP-1559 transactions, transaction.MaxFeePerGas and transaction.MaxPriorityFeePerGas are populated instead of transaction.GasPrice. The transaction.Type field indicates the transaction type (0x0 = legacy, 0x2 = EIP-1559).

Get a Transaction Receipt​

The receipt contains the execution result after a transaction has been mined:

var receipt = await web3.Eth.Transactions.GetTransactionReceipt
    .SendRequestAsync(
        "0xb4729a0d8dd30e3070d0cb203090f2b792e029f6fa4629e96d2ebc1de13cb5c4");

Console.WriteLine("Transaction Hash: " + receipt.TransactionHash);
Console.WriteLine("Logs count: " + receipt.Logs.Count);

The receipt includes Status (1 = success, 0 = revert), GasUsed, EffectiveGasPrice, Logs (raw event logs), BlockNumber, and TransactionIndex.

GetTransactionReceipt returns null if the transaction has not been mined yet. Use receipt.HasErrors() to check if the transaction reverted.

Get Transaction Count (Nonce)​

The transaction count for an address is its nonce (the transaction sequence number for an address) — the number of transactions sent from that address:

var nonce = await web3.Eth.Transactions.GetTransactionCount
    .SendRequestAsync("0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae");
Console.WriteLine("Nonce: " + nonce.Value);

Detect if an Address is a Contract​

Use GetCode to check whether an address has deployed bytecode. Externally owned accounts (EOAs) return "0x":

var code = await web3.Eth.GetCode.SendRequestAsync("0xaddress...");
var isContract = code != null && code != "0x";
Console.WriteLine("Is contract: " + isContract);

Decode Events from a Receipt​

Use DecodeAllEvents<T>() to decode typed events from a transaction receipt. TransferEventDTO is a built-in type from Nethereum.Contracts.Standards.ERC20:

using Nethereum.Contracts;
using Nethereum.Contracts.Standards.ERC20.ContractDefinition;

var receipt = await web3.Eth.Transactions.GetTransactionReceipt
    .SendRequestAsync("0x654288d8...");

var transferEvents = receipt.DecodeAllEvents<TransferEventDTO>();
foreach (var e in transferEvents)
{
    Console.WriteLine($"From: {e.Event.From}, To: {e.Event.To}, Value: {e.Event.Value}");
}

Next Steps​