Question

我正在尝试使用fs模块从目录中读取文件，并在Electron应用程序中使用id displayfiles在div中显示该文件。我不断收到错误消息：

 Cannot read property 'send' of undefined

这是我的renderer.js

// This file is required by the index.html file and will
// be executed in the renderer process for that window.
// All of the Node.js APIs are available in this process.
const electron = require('electron');
const dialog = electron.dialog;
const fs = require('fs');
const remote = require ("electron").remote;
const ipcRenderer = electron.ipcRenderer;
const template=[
    {
        label: 'File',
        submenu: [
            {
                label:'Open USB',
                click () { dialog.showOpenDialog( {
                    properties: ['openDirectory']
                },directorySelectorCallback)

                }
            },
            {
                label:'Exit',
                click() {

                }
            },
        ]
    },
    {
        label: 'Edit',
        submenu: [
            {role: 'undo'},
            {role: 'redo'},
            {type: 'separator'},
            {role: 'cut'},
            {role: 'copy'},
            {role: 'paste'},
            {role: 'pasteandmatchstyle'},
            {role: 'delete'},
            {role: 'selectall'}
        ]
    },
    {
        label: 'View',
        submenu: [
            {role: 'reload'},
            {role: 'forcereload'},
            {role: 'toggledevtools'},
            {type: 'separator'},
            {role: 'resetzoom'},
            {role: 'zoomin'},
            {role: 'zoomout'},
            {type: 'separator'},
            {role: 'togglefullscreen'}
        ]
    },
    {
        role: 'window',
        submenu: [
            {role: 'minimize'},
            {role: 'close'}
        ]
    },
]

function directorySelectorCallback(filenames) {
    if (filenames && filenames.length > 0) {
        console.log(filenames[0]);
        fs.readdir(filenames[0], (err, files) => {
            'use strict';
            if (err) throw  err;
            //the files parameter is an array of the files and folders in the path we passed. So we loop through the array, printing each file and folder
            for (let file of files) {
                console.log(file);
                ipcRenderer.send('add-file', 'an-document.getElementById(\'display-files\').innerHTML += `<li>${file}</li>`;')

            }
        });
    }
}
module.exports.template=template;

这是我的main.js代码：

// Modules to control application life and create native browser window
const electron = require('electron')
const {app, BrowserWindow,Menu,ipcMain} = require('electron')
const menuTemplate=require('./renderer.js').template
// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
var mainWindow=null;

function createWindow () {
  // Create the browser window.
  mainWindow = new BrowserWindow({width: 800, height: 600,icon: __dirname + '/Rexnord.ico'})

  // and load the index.html of the app.
  mainWindow.loadFile('index.html')

  // Open the DevTools.
   mainWindow.webContents.openDevTools()
  // Emitted when the window is closed.
  mainWindow.on('closed', function () {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null
  })
    let menu = Menu.buildFromTemplate(menuTemplate)
    Menu.setApplicationMenu(menu);
}
ipcMain.on('add-file', (event, arg)=> {
   mainWindow.webContents.executeJavaScript(arg);
})
// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', createWindow)
// Quit when all windows are closed.
app.on('window-all-closed', function () {
  // On macOS it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', function () {
  // On macOS it's common to re-create a window in the app when the
  // dock icon is clicked and there are no other windows open.
  if (mainWindow === null) {
    createWindow()
  }
})

// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.

我正在尝试与ipc模块进行renderer.js和main.js文件之间的通信。根据我的阅读，我应该能够通过通道将ipcrenderer模块发送到主进程的消息，但是我一直收到此错误。有人可以告诉我我在做什么错吗？

Answer 1

您的问题是您require(./renderer)来自 Main 进程。

这是必要的，因为Menu是 Main 处理模块
OTOH ipcRenderer在 Main 流程中未定义，因此在回调中也将不可用

您应该重新构建代码，以不要使用Main和Renderer中的renderer.js 两者。

由于您仅向Main发送消息以在Renderer中执行代码，因此您可以简单地在ipcRenderer上设置侦听器来操作DOM并在Main进程（click的{{3} }使其变得容易）。

main.js

const { app, BrowserWindow, Menu } = require('electron')
const path = require('path')
const { menuTemplate } = require('./template')

app.once('ready', () => {
  let win = new BrowserWindow()
  win.loadURL(path.join(__dirname, '/index.html'))

  let menu = Menu.buildFromTemplate(menuTemplate)
  Menu.setApplicationMenu(menu)
})

template.js

const { dialog } = require('electron')
const fs = require('fs')

module.exports = {
  menuTemplate: [
    {
      label: 'File',
      submenu: [
        {
          label: 'Open USB',
          click (menuItem, browserWindow, event) {
            dialog.showOpenDialog({
              properties: ['openDirectory']
            }, ([dir]) => {
              try {
                if (fs.statSync(dir).isDirectory()) {
                  const files = fs.readdirSync(dir)
                  browserWindow.webContents.send('add-file', files)
                }
              } catch (err) {
                console.error(err)
              }
            })
          }
        }
      ]
    }
  ]
}

index.html

<html>
  <body>
    <script>
      const { ipcRenderer } = require('electron')
      ipcRenderer.on('add-file', (event, files) => {
        files.forEach(f => {
          document.getElementById('display-files').innerHTML +=
            `<li>${f}</li>`
        })
      })
    </script>
    <div id='display-files'>
      Files:
    </div>
  </body>
</html>

电子：无法读取未定义的属性“发送”

1 个答案: