c#使用类库nthereum在.net上开发以太坊的实战示例

这是一篇文章的早期版本，旨在帮助那些对以太坊区块链平台有基本了解的开发人员，如果想学习如何使用Nethereum .NET库对Ethereum平台进行编程。

我以后会在这篇文章中添加更多内容，但就目前而言，正在使用它发布.NET 10+的系列C＃示例，介绍如何使用Nethereum库执行针对以太坊区块链平台的最常见任务。

最常见任务列表包括以下内容：

• 1.获取协议版本
• 2.获取最大块数
• 3.获取帐户余额
• 4.发送以太
• 5.等待交易收据
• 6.在区块链中扫描块
• 7.列出个人账户（及其余额）
• 8.在区块链中扫描交易
• 9.与现有（已部署）合同互动
• 10.用事件和现有（已部署）合约交互
• 11.获取所有活动更改
• 12.获取合约金额历史

这里是c#的主文件：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

using Nethereum.Hex.HexTypes;
using Nethereum.Web3;

namespace MWH.MyNethereum.QuickRef
{
 static public class TaskExamples
 {
 const int UNLOCK_TIMEOUT = 2 * 60; // 2 minutes (arbitrary)
 const int SLEEP_TIME = 5 * 1000; // 5 seconds (arbitrary)
 const int MAX_TIMEOUT = 2 * 60 * 1000; // 2 minutes (arbirtrary)

// These static public variables do not represent a recommended pattern
 static public string LastProtocolVersion = "";
 static public string LastTxHash = "";
 static public Nethereum.RPC.Eth.DTOs.TransactionReceipt LastTxReceipt = null;
 static public HexBigInteger LastMaxBlockNumber = new HexBigInteger(0);

static public async Task GetProtocolVersionExample(Web3 web3)
 {
 Console.WriteLine("GetProtocolVersionExample:");

var protocolVersion = await web3.Eth.ProtocolVersion.SendRequestAsync();
 Console.WriteLine("protocolVersion:	" + protocolVersion.ToString());
 LastProtocolVersion = protocolVersion;
 }

static public async Task GetMaxBlockExample(Web3 web3)
 {
 Console.WriteLine("GetMaxBlockExample:");

var maxBlockNumber = await web3.Eth.Blocks.GetBlockNumber.SendRequestAsync();
 Console.WriteLine("maxBlockNumber:	" + maxBlockNumber.Value.ToString());
 LastMaxBlockNumber = maxBlockNumber;
 }

static public async Task ScanBlocksExample(Web3 web3, ulong startBlockNumber, ulong endBlockNumber)
 {
 Console.WriteLine("ScanBlocksExample:");

long txTotalCount = 0;
 for (ulong blockNumber = startBlockNumber; blockNumber <= endBlockNumber; blockNumber++)
 {
 var blockParameter = new Nethereum.RPC.Eth.DTOs.BlockParameter(blockNumber);
 var block = await web3.Eth.Blocks.GetBlockWithTransactionsByNumber.SendRequestAsync(blockParameter);
 var trans = block.Transactions;
 int txCount = trans.Length;
 txTotalCount += txCount;
 if (blockNumber % 1000 == 0) Console.Write(".");
 if (blockNumber % 10000 == 0)
 {
 DateTime blockDateTime = Helpers.UnixTimeStampToDateTime((double)block.Timestamp.Value);
 Console.WriteLine(blockNumber.ToString() + " " + txTotalCount.ToString() + " " + blockDateTime.ToString());
 }
 }
 Console.WriteLine();
 }

static public async Task ScanTxExample(Web3 web3, ulong startBlockNumber, ulong endBlockNumber)
 {
 Console.WriteLine("ScanTxExample:");

long txTotalCount = 0;
 for (ulong blockNumber = startBlockNumber; blockNumber <= endBlockNumber; blockNumber++)
 {
 var blockParameter = new Nethereum.RPC.Eth.DTOs.BlockParameter(blockNumber);
 var block = await web3.Eth.Blocks.GetBlockWithTransactionsByNumber.SendRequestAsync(blockParameter);
 var trans = block.Transactions;
 int txCount = trans.Length;
 txTotalCount += txCount;
 foreach (var tx in trans)
 {
 try
 {
 var bn = tx.BlockNumber.Value;
 var th = tx.TransactionHash;
 var ti = tx.TransactionIndex.Value;

var rpt = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(th);
 var status = rpt.Status.Value;

var nc = tx.Nonce.Value;
 var from = tx.From;

Console.WriteLine(th.ToString() + " " + ti.ToString() + " " + from.ToString() + " " + status.ToString());

var to = tx.To;
 if (to == null) to = "to:NULL";
 var v = tx.Value.Value;
 var g = tx.Gas.Value;
 var gp = tx.GasPrice.Value;
 Console.WriteLine(th.ToString() + " " + ti.ToString() + " " + nc.ToString() + " " + from.ToString() + " " + to.ToString() + " " + v.ToString() + " " + g.ToString() + " " + gp.ToString());
 }
 catch (Exception ex)
 {
 Console.WriteLine("ScanTxExample.Tx:	" + ex.ToString());
 if (ex.InnerException != null) Console.WriteLine("ScanTxExample.Tx:	" + ex.InnerException.ToString());
 }
 }
 Console.WriteLine();
 }
 }

static public async Task GetAccountBalanceExample(Web3 web3, string accountAddress)
 {
 Console.WriteLine("GetAccountBalanceExample:");

var balanceWei = await web3.Eth.GetBalance.SendRequestAsync(accountAddress);
 var balanceEther = Web3.Convert.FromWei(balanceWei.Value);
 Console.WriteLine("accountAddress:	" + accountAddress.ToString());
 Console.WriteLine("balanceEther:	" + balanceEther.ToString());
 }

static public async Task ListPersonalAccountsExample(Web3 web3)
 {
 Console.WriteLine("ListPersonalAccountsExample:");

var accounts = await web3.Personal.ListAccounts.SendRequestAsync();
 foreach (var account in accounts)
 {
 var balanceWei = await web3.Eth.GetBalance.SendRequestAsync(account);
 var balanceEther = Web3.Convert.FromWei(balanceWei.Value);
 Console.WriteLine("account:	" + account + " balanceEther:	" + balanceEther.ToString());
 }
 }

static public async Task SendEtherExample(Web3 web3, string fromAddress, string fromPassword, string toAddress, long amountWei)
 {
 Console.WriteLine("SendEtherExample:");

var unlockResult = await web3.Personal.UnlockAccount.SendRequestAsync(fromAddress, fromPassword, UNLOCK_TIMEOUT);
 var sendTxHash = await web3.Eth.TransactionManager.SendTransactionAsync(fromAddress, toAddress, new HexBigInteger(amountWei));
 Console.WriteLine("fromAddress:	" + fromAddress.ToString());
 Console.WriteLine("toAddress:	" + toAddress.ToString());
 Console.WriteLine("amountWei:	" + amountWei.ToString());
 Console.WriteLine("sendTxHash:	" + sendTxHash.ToString());
 LastTxHash = sendTxHash;
 }

static public async Task WaitForTxReceiptExample(Web3 web3, string txHash)
 {
 Console.WriteLine("WaitForTxReceiptExample:");

int timeoutCount = 0;
 var txReceipt = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash);
 while (txReceipt == null && timeoutCount < MAX_TIMEOUT)
 {
 Console.WriteLine("Sleeping...");
 Thread.Sleep(SLEEP_TIME);
 txReceipt = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash);
 timeoutCount += SLEEP_TIME;
 }
 Console.WriteLine("timeoutCount " + timeoutCount.ToString());
 LastTxReceipt = txReceipt;
 }

static public async Task InteractWithExistingContractExample(Web3 web3, string fromAddress, string fromPassword, string contractAddress, string contractAbi)
 {
 Console.WriteLine("InteractWithExistingContractExample:");

var contract = web3.Eth.GetContract(contractAbi, contractAddress);

var setMessageFunction = contract.GetFunction("setMsg");
 var getMessageFunction = contract.GetFunction("getMsg");

string nowTimestamp = DateTime.UtcNow.ToString() + " UTC";
 Console.WriteLine("now:	" + nowTimestamp);

var unlockResult = await web3.Personal.UnlockAccount.SendRequestAsync(fromAddress, fromPassword, UNLOCK_TIMEOUT);
 var txHash1 = await setMessageFunction.SendTransactionAsync(fromAddress, new HexBigInteger(900000), null, 1, "Hello World");
 Console.WriteLine("txHash1:	" + txHash1.ToString());
 var txHash2 = await setMessageFunction.SendTransactionAsync(fromAddress, new HexBigInteger(900000), null, 2, nowTimestamp);
 Console.WriteLine("txHash2:	" + txHash2.ToString());

var txReceipt2 = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash2);
 int timeoutCount = 0;
 while (txReceipt2 == null && timeoutCount < MAX_TIMEOUT)
 {
 Console.WriteLine("Sleeping...");
 Thread.Sleep(SLEEP_TIME);
 txReceipt2 = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash2);
 timeoutCount += SLEEP_TIME;
 }
 Console.WriteLine("timeoutCount:	" + timeoutCount.ToString());

var txReceipt3 = await setMessageFunction.SendTransactionAndWaitForReceiptAsync(fromAddress, new HexBigInteger(900000), null, null, 2, nowTimestamp + " Wait");
 Console.WriteLine("txReceipt3:	" + txReceipt3.TransactionHash.ToString());
 Console.WriteLine("txReceipt3:	" + txReceipt3.CumulativeGasUsed.Value.ToString());

var getResult1 = await getMessageFunction.CallAsync<string>(1);
 Console.WriteLine("getResult1:	" + getResult1.ToString());
 var getResult2 = await getMessageFunction.CallAsync<string>(2);
 Console.WriteLine("getResult2:	" + getResult2.ToString());
 }

static public async Task InteractWithExistingContractWithEventsExample(Web3 web3, string fromAddress, string fromPassword, string contractAddress, string contractAbi)
 {
 Console.WriteLine("InteractWithExistingContractWithEventsExample:");

var contract = web3.Eth.GetContract(contractAbi, contractAddress);

var setMessageFunction = contract.GetFunction("setMsg");
 var getMessageFunction = contract.GetFunction("getMsg");
 var multipliedEvent = contract.GetEvent("MultipliedEvent");
 var newMessageEvent = contract.GetEvent("NewMessageEvent");

var filterAllMultipliedEvent = await multipliedEvent.CreateFilterAsync();
 var filterAllNewMessageEvent = await newMessageEvent.CreateFilterAsync();

string nowTimestamp = DateTime.UtcNow.ToString() + " UTC";
 Console.WriteLine("now:	" + nowTimestamp);

var unlockResult = await web3.Personal.UnlockAccount.SendRequestAsync(fromAddress, fromPassword, UNLOCK_TIMEOUT);
 var txHash1 = await setMessageFunction.SendTransactionAsync(fromAddress, new HexBigInteger(900000), null, 1, "Hello World");
 Console.WriteLine("txHash1:	" + txHash1.ToString());
 var txHash2 = await setMessageFunction.SendTransactionAsync(fromAddress, new HexBigInteger(900000), null, 2, nowTimestamp);
 Console.WriteLine("txHash2:	" + txHash2.ToString());

var txReceipt2 = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash2);
 int timeoutCount = 0;
 while (txReceipt2 == null && timeoutCount < MAX_TIMEOUT)
 {
 Console.WriteLine("Sleeping...");
 Thread.Sleep(SLEEP_TIME);
 txReceipt2 = await web3.Eth.Transactions.GetTransactionReceipt.SendRequestAsync(txHash2);
 timeoutCount += SLEEP_TIME;
 }
 Console.WriteLine("timeoutCount:	" + timeoutCount.ToString());

var txReceipt3 = await setMessageFunction.SendTransactionAndWaitForReceiptAsync(fromAddress, new HexBigInteger(900000), null, null, 2, nowTimestamp + " Wait");
 Console.WriteLine("txReceipt3:	" + txReceipt3.TransactionHash.ToString());
 Console.WriteLine("txReceipt3:	" + txReceipt3.CumulativeGasUsed.Value.ToString());

var getResult1 = await getMessageFunction.CallAsync<string>(1);
 Console.WriteLine("getResult1:	" + getResult1.ToString());
 var getResult2 = await getMessageFunction.CallAsync<string>(2);
 Console.WriteLine("getResult2:	" + getResult2.ToString());

var logMultipliedEvents = await multipliedEvent.GetFilterChanges<FunctionOutputHelpers.MultipliedEventArgs>(filterAllMultipliedEvent);
 foreach (var mea in logMultipliedEvents)
 {
 Console.WriteLine("multipliedEvent:	" +
 mea.Event.sender + " " + mea.Event.oldProduct.ToString() + " " + mea.Event.value.ToString() + " " + mea.Event.newProduct.ToString());
 }

var logNewMessageEvents = await newMessageEvent.GetFilterChanges<FunctionOutputHelpers.NewMessageEventArgs>(filterAllNewMessageEvent);
 foreach (var mea in logNewMessageEvents)
 {
 Console.WriteLine("newMessageEvent:	" +
 mea.Event.sender + " " + mea.Event.ind.ToString() + " " + mea.Event.msg.ToString());
 }
 }

static public async Task GetAllChangesExample(Web3 web3, string fromAddress, string fromPassword, string contractAddress, string contractAbi)
 {
 Console.WriteLine("GetAllChangesExample:");

var contract = web3.Eth.GetContract(contractAbi, contractAddress);
 var newMessageEvent = contract.GetEvent("NewMessageEvent");
 var filterAllNewMessageEvent = await newMessageEvent.CreateFilterAsync(fromAddress);
 var logNewMessageEvents = await newMessageEvent.GetAllChanges<FunctionOutputHelpers.NewMessageEventArgs>(filterAllNewMessageEvent);
 foreach (var mea in logNewMessageEvents)
 {
 Console.WriteLine("newMessageEvent:	" +
 mea.Event.sender + " " + mea.Event.ind.ToString() + " " + mea.Event.msg.ToString());
 }
 }

static public async Task GetContractValuesHistoryUniqueOffsetValueExample(Web3 web3, string contractAddress, HexBigInteger recentBlockNumber, ulong numberBlocks, int offset)
 {
 Console.WriteLine("GetContractValuesHistoryUniqueOffsetValueExample:");

string previousValue = "";
 for (ulong blockNumber = (ulong)recentBlockNumber.Value; blockNumber > (ulong)recentBlockNumber.Value - numberBlocks; blockNumber--)
 {
 var blockNumberParameter = new Nethereum.RPC.Eth.DTOs.BlockParameter(blockNumber);
 var valueAtOffset = await web3.Eth.GetStorageAt.SendRequestAsync(contractAddress, new HexBigInteger(offset), blockNumberParameter);
 if (valueAtOffset != previousValue)
 {
 var block = await web3.Eth.Blocks.GetBlockWithTransactionsByNumber.SendRequestAsync(blockNumberParameter);
 DateTime blockDateTime = Helpers.UnixTimeStampToDateTime((double)block.Timestamp.Value);
 Console.WriteLine("blockDateTime:	" + blockDateTime.ToString());

for (int storageOffset = 0; storageOffset < offset+2; storageOffset++)
 {
 var valueAt = await web3.Eth.GetStorageAt.SendRequestAsync(contractAddress, new HexBigInteger(storageOffset), blockNumberParameter);
 Console.WriteLine("value:	" + blockNumber.ToString() + " " + storageOffset.ToString() + " " + valueAt + " " + Helpers.ConvertHex(valueAt.Substring(2)));
 }
 previousValue = valueAtOffset;
 }
 }
 }
 }
}

以下是一些支持文件：

FunctionOutputHelpers.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Nethereum.Web3;
using Nethereum.ABI.FunctionEncoding.Attributes;

namespace MWH.MyNethereum.QuickRef
{
 static public class FunctionOutputHelpers
 {
 // event MultipliedEvent(
 // address indexed sender,
 // int oldProduct,
 // int value,
 // int newProduct
 // );

[FunctionOutput]
 public class MultipliedEventArgs
 {
 [Parameter("address", "sender", 1, true)]
 public string sender { get; set; }

[Parameter("int", "oldProduct", 2, false)]
 public int oldProduct { get; set; }

[Parameter("int", "value", 3, false)]
 public int value { get; set; }

[Parameter("int", "newProduct", 4, false)]
 public int newProduct { get; set; }

}

//event NewMessageEvent(
 // address indexed sender,
 // uint256 indexed ind,
 // string msg
 //);

[FunctionOutput]
 public class NewMessageEventArgs
 {
 [Parameter("address", "sender", 1, true)]
 public string sender { get; set; }

[Parameter("uint256", "ind", 2, true)]
 public int ind { get; set; }

[Parameter("string", "msg", 3, false)]
 public string msg { get; set; }
 }
 }
}

Helpers.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MWH.MyNethereum.QuickRef
{
 static public class Helpers
 {
 public static string ConvertHex(String hexString)
 {
 try
 {
 string ascii = string.Empty;

for (int i = 0; i < hexString.Length; i += 2)
 {
 String hs = string.Empty;

hs = hexString.Substring(i, 2);
 uint decval = System.Convert.ToUInt32(hs, 16);
 char character = System.Convert.ToChar(decval);
 ascii += character;

}

return ascii;
 }
 catch (Exception ex) { Console.WriteLine(ex.Message); }

return string.Empty;
 }

public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
 {
 // Unix timestamp is seconds past epoch
 System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
 dtDateTime = dtDateTime.AddSeconds(unixTimeStamp); // .ToLocalTime();
 return dtDateTime;
 }

public static DateTime JavaTimeStampToDateTime(double javaTimeStamp)
 {
 // Java timestamp is milliseconds past epoch
 System.DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
 dtDateTime = dtDateTime.AddMilliseconds(javaTimeStamp); // .ToLocalTime();
 return dtDateTime;
 }
 }
}

以下是用于实施这些示例时使用的以太坊合约的Solidity代码：

Test3.sol

pragma solidity 0.4.19;

contract Test3 {

int public _product;
string[5] _msgs;
 
event MultipliedEvent(
address indexed sender,
int oldProduct,
int value,
int newProduct
);
 
event NewMessageEvent(
address indexed sender,
uint256 indexed ind,
string msg
);

function Test3() public {
_product = 1;
}

function multiply(int value) public returns(int product) {
int old = _product;
_product = value * _product;
MultipliedEvent( msg.sender, old, value, _product );
return _product;
}
 
function getProduct() public constant returns(int product) {
return _product;
}

function setMsg(uint256 i, string m) public returns(uint256 mi) {
_msgs[i] = m;
NewMessageEvent( msg.sender, i, m);
return -i;
}

function getMsg(uint256 index) public constant returns(string m) {
return _msgs[index];
}
}

我觉得这是发布代码示例的一种相当简单粗暴的方式。有任何更好建议欢迎留言。