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首页 > 解决方案 > web3.eth.accounts[0] 返回 undefined 并且 app.vote(1,{ from:web3.eth.accounts[0] }) 给出错误

javascript - web3.eth.accounts[0] 返回 undefined 并且 app.vote(1,{ from:web3.eth.accounts[0] }) 给出错误

问题描述

我是 Solidity 的新手，正在通过一个简单的 web 应用程序来探索它。我正在尝试制作一个候选人投票网络应用程序，它接受一些详细信息和一个按钮，详细信息应部署到智能合约创建的块中。当我尝试web3.eth.accounts[0]在 truffle 控制台中使用获取帐户详细信息时，它返回 undefined 。当我尝试使用 truffle 控制台从账户 1 向候选人 1 发送投票时app.vote(1,{ from:web3.eth.accounts[0] })，我收到如下错误：

truffle(development)> web3.eth.accounts[0]
undefined
truffle(development)> app.vote(1,{ 
from:web3.eth.accounts[0] })
Thrown:
Error: The send transactions "from" field 
must be defined!
at evalmachine.<anonymous>:0:5
at sigintHandlersWrap (vm.js:272:15)
at Script.runInContext (vm.js:127:14)
at runScript
at bound (domain.js:426:14)
    at REPLServer.runBound [as eval] (domain.js:439:12)
    at REPLServer.onLine (repl.js:726:10)
    at REPLServer.emit (events.js:219:5)
    at REPLServer.EventEmitter.emit (domain.js:482:12)
    at REPLServer.Interface._onLine (readline.js:324:10)
    at REPLServer.Interface._line (readline.js:701:8)
    at REPLServer.Interface._ttyWrite (readline.js:1026:14)
    at REPLServer.self._ttyWrite (repl.js:803:7)
    at ReadStream.onkeypress (readline.js:200:10)
    at ReadStream.emit (events.js:219:5)
    at ReadStream.EventEmitter.emit (domain.js:482:12)
    at emitKeys (internal/readline/utils.js:438:14)
    at emitKeys.next (<anonymous>) {
  hijackedStack: 'Error: The send transactions "from" field must be defined!\n' +
    '    at Method.inputTransactionFormatter (C:\\npm\\node_modules\\truffle\\build\\webpack:\\node_modules\\web3-core-helpers\\src\\formatters.js:142:1)\n' +
    '    at C:\\npm\\node_modules\\truffle\\build\\webpack:\\node_modules\\web3-core-method\\src\\index.js:144:1\n' +
    '    at Array.map (<anonymous>)\n' +
    '    at Method.formatInput (C:\\npm\\node_modules\\truffle\\build\\webpack:\\node_modules\\web3-core-method\\src\\index.js:142:1)\n' +
    '    at Method.toPayload (C:\\npm\\node_modules\\truffle\\build\\webpack:\\node_modules\\web3-core-method\\src\\index.js:177:1)\n' +
    '    at Eth.send [as sendTransaction] (C:\\npm\\node_modules\\truffle\\build\\webpack:\\node_modules\\web3-core-method\\src\\index.js:467:1)\n' +
    '    at Object.sendTransaction (C:\\npm\\node_modules\\truffle\\build\\webpack:\\packages\\contract\\lib\\execute.js:486:1)\n' +
    '    at C:\\npm\\node_modules\\truffle\\build\\webpack:\\packages\\contract\\lib\\execute.js:203:1\n' +
    '    at processTicksAndRejections (internal/process/task_queues.js:97:5)'
}

标签： javascriptethereumsolidityweb3jsmetamask

解决方案

您收到此错误是因为未定义 from 字段，当您传递它undefined时，您可以在运行它时看到truffle(development)> web3.eth.accounts[0]它返回undefined。这是因为这是一个异步方法，这意味着当您发送交易时，您需要等待accounts 方法完成。

因此，您应该这样做（考虑到web3.eth.accounts已弃用并且每次都输入 await 很乏味）：

truffle(development)> let accounts = await web3.eth.getAccounts()
truffle(development)> app.vote(1,{ from: accounts[0] })

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