为啥我的 ipcMain 没有发送到 Electron 中的 ipcRenderer？
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【中文标题】为啥我的 ipcMain 没有发送到 Electron 中的 ipcRenderer？【英文标题】：Why is my ipcMain not sending to ipcRenderer in Electron?为什么我的 ipcMain 没有发送到 Electron 中的 ipcRenderer？ 【发布时间】：2019-08-11 11:36:09 【问题描述】：电子新手我已经知道如何从 Renderer 发送到 Main 但我正在尝试学习如何从 Main 到渲染器。在我的研究中，我读到：
IPC send from main process to renderer 并尝试过：
main.js：
const app, ipcMain, Menu = require('electron')
const appVersion = process.env.npm_package_version
const mainWindow = require('./renderer/mainWindow')
app.on('ready', () =>
mainWindow.createWindow(),
console.log(`Trying to send app version to renderer: $appVersion`),
mainWindow.webContents.send('app-version', appVersion),
Menu.setApplicationMenu(mainMenu)
)
但我收到以下错误：
Uncaught Exception TypeError Cannot read property 'send' of undefined
读完“Send sync message from IpcMain to IpcRenderer - Electron”后我试了一下：
ipcMain.on('app-version', (event) =>
console.log(`Sent: $appVersion`)
event.sender.send(appVersion)
),
但没有任何反应或错误。我的 renderer.js：
const ipcRenderer = require('electron')
ipcRenderer.on('app-version', (event, res) =>
console.log(res)
)
为什么我的 ipcMain 没有发送到我的 ipcRenderer？
编辑：
mainWindow.js：
// Modules
const BrowserWindow = require('electron')
// export mainWindow
exports.createWindow = () =>
// BrowserWindow options
// https://electronjs.org/docs/api/browser-window#new-browserwindowoptions
this.win = new BrowserWindow(
minWidth: 400,
minHeight: 400,
frame: false,
webPreferences:
nodeIntegration: true,
backgroundThrottling: false
)
// Devtools
this.win.webContents.openDevTools()
// Load main window content
this.win.loadURL(`file://$__dirname/index.html`)
// Handle window closed
this.win.on('closed', () =>
this.win = null
)
我也试过了：
main.js：
app.on('ready', () =>
mainWindow.createWindow(),
mainWindow.win.webContents.send('app-version', appVersion),
Menu.setApplicationMenu(mainMenu)
)
renderer.js：
console.log("Trying")
ipcRenderer.on('app-version', (args) =>
console.log(`Node version is $args`)
)
由于某种原因，现在我编写的 ipcMain 应用的答案多次发送到渲染器并重复渲染控制台消息
Trying to send app version to renderer: 1.0.0
Trying to send app version to renderer: 1.0.0
Trying to send app version to renderer: 1.0.0
Trying to send app version to renderer: 1.0.0
Trying to send app version to renderer: 1.0.0
现在应用程序闪烁，但在 console.log 中显示一次，我不明白为什么。
编辑
回复answer。
我知道app.getVersion 我只是在使用ENV 来学习如何发送到main。测试代码后，这种方法不起作用。
应对：
app.on('ready', () =>
const win = mainWindow.createWindow(),
console.log(`Trying to send app version to renderer: $appVersion`),
win.webContents.send('app-version', appVersion),
Menu.setApplicationMenu(mainMenu)
)
抛出以下错误：
const 声明中缺少初始化程序
如此修改：
app.on('ready', () =>
const win = mainWindow.createWindow()
console.log(`Trying to send app version to renderer: $appVersion`)
win.webContents.send('app-version', appVersion)
Menu.setApplicationMenu(mainMenu)
)
但是在exports.createWindow末尾添加return时会抛出这个错误：
win 没有定义
在exports.createWindow 之前添加let.win 不会抛出任何代码，但不会发送任何内容。
Electron Fiddle
index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Electron learning</title>
<!-- CSS Bootstrap -->
<!-- <link rel="stylesheet" href="../node_modules/bootstrap/dist/css/bootstrap.css"> -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<!--
Font Awesome
https://fontawesome.com/v4.7.0/cheatsheet/
-->
<!-- <link rel="stylesheet" href="../node_modules/font-awesome/css/font-awesome.css"> -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<!-- Custom CSS -->
<style>
body
-webkit-app-region: drag;
footer
position: fixed;
bottom: 0;
width: 100%;
#close_app,
#site
cursor: pointer;
</style>
</head>
<body class="d-flex flex-column h-100">
<header>
<nav class="navbar navbar-expand navbar-dark fixed-top bg-dark">
<a class="navbar-brand text-white">Foobar</a>
<div class="collapse navbar-collapse justify-content-between">
<div class="navbar-nav">
<a id="site" class="nav-link"><small><u id="application"></u></small></a>
</div>
<div class="navbar-nav">
<a id="close_app" class="nav-item nav-link"><i class="fa fa-times-circle"></i></a>
</div>
</div>
</nav>
</header>
<main role="main" class="flex-shrink-0">
<div class="container">
<h1>Hello World!</h1>
<!-- All of the Node.js APIs are available in this renderer process. -->
We are using Node.js <script>document.write(process.versions.node)</script>,
Chromium <script>document.write(process.versions.chrome)</script>,
and Electron <script>document.write(process.versions.electron)</script>.
Electron app version <script>document.write(process.versions.electron)</script>.
</div>
<p id="testSender"></p>
</main>
<footer class="footer mt-auto py-3 ">
<div class="container">
<span class="text-muted">Place sticky footer content here.</span>
</div>
</footer>
<script>
// jQuery
// window.jQuery = window.$ = $ = require('jquery')
// You can also require other files to run in this process
require('./renderer.js')
</script>
<!-- <script src="../node_modules/jquery/dist/jquery.min.js"></script> -->
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<!-- <script src="../node_modules/bootstrap/dist/js/bootstrap.min.js"></script> -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>
main.js:
'use strict'
// Modules to control application life and create native browser window
const app, ipcMain, BrowserWindow, Menu = require('electron')
const testMainSend = `Trying to send something to renderer`
let mainWindow
// Window state keeper
const windowStateKeeper = require('electron-window-state')
// export mainWindow
function createWindow ()
let winState = windowStateKeeper(
defaultWidth: 400,
defaultHeight: 400
)
// BrowserWindow options
// https://electronjs.org/docs/api/browser-window#new-browserwindowoptions
const win = new BrowserWindow(
width: winState.width,
height: winState.Height,
x: winState.x,
y: winState.y,
minWidth: 400,
minHeight: 400,
frame: false,
webPreferences:
nodeIntegration: true,
backgroundThrottling: false
)
winState.manage(win)
// Devtools
win.webContents.openDevTools()
// Load main window content
win.loadURL(`file://$__dirname/index.html`)
// Handle window closed
win.on('closed', () =>
this.win = null
)
return win
// 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()
// 1st attempt
// webContents.send('misc-sender', testMainSend)
// 2nd attempt
// const win = createWindow()
// win.webContents.send('misc-sender', testMainSend)
// 3rd attempt
const win = createWindow()
win.webContents.on('dom-ready', () =>
console.log(`Trying to send renderer: $testMainSend`)
mainWindow.win.webContents.send('misc-sender', testMainSend)
)
)
// Quit when all windows are closed.
app.on('window-all-closed', () =>
// 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', () =>
// 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()
)
// Close application from button
ipcMain.on('closing-app', () =>
app.quit()
console.log('Closed app from font awesome link')
)
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 ipcRenderer, shell = require('electron')
const appVersion = require('electron').remote.app.getVersion()
// Devtron
// require('devtron').install()
// Close App
const closeApp = document.getElementById('close_app')
closeApp.addEventListener('click', () =>
ipcRenderer.send('closing-app')
)
// received from ipcMain test
ipcRenderer.on('misc-sender', (event, args) =>
appendTest = document.getElementById('testSender')
appendTest.innerHTML += args
)
// Getting version
const appVersioning = document.getElementById('application')
appVersioning.innerHTML = appVersion
// Open site
const homeURL = document.getElementById('site')
homeURL.addEventListener('click', (e) =>
e.preventDefault
shell.openExternal("https://www.google.com/")
)
【问题讨论】：
这里有很多编辑和更正的语法错误，很难知道发生了什么。发布电子小提琴（github.com/electron/fiddle）的链接，然后我可以提供更多帮助。 AFAICT，您所做的基本上是正确的，您可能只是在将该消息发送到 webContents 和 webContents 及时收听它时遇到了一些竞争条件。 @ccnokes 进行了另一次编辑以包含来自 Electron Fiddle 的所有内容。 @Grim 我做了一些小改动来修复语法错误，一切正常。所以你做的是对的，只是被小细节绊倒了。这是工作小提琴 URL：gist.github.com/ccnokes/5150ebd95d4368048513e73f5c7d57be 【参考方案1】：经过多次搜索和尝试，我想我终于知道如何将我的应用程序版本从 package.json 发送到 main 然后再发送到渲染器。我的问题出在我的app.on 中，我错过了dom-ready，这在阅读IPC Communication not working between Electron and window 后有所帮助：
main.js：
const appVersion = process.env.npm_package_version
app.on('ready', () =>
mainWindow.createWindow()
Menu.setApplicationMenu(mainMenu)
// Send version to renderer
mainWindow.win.webContents.on('dom-ready', () =>
console.log(`Trying to send app version to renderer: $appVersion`)
mainWindow.win.webContents.send('app-version', appVersion)
)
)
renderer.js：
ipcRenderer.on('app-version', (event, args) =>
const appVersion = document.getElementById('app_version')
console.log(`Node version is $args`)
appVersion.innerHTML += args
)
index.html：
<div id="app_version"></div>
可能有更好的方法来做到这一点，但经过进一步研究，我读到：
Electron - How to know when renderer window is readydom-ready 来自instance-events
这可行，但下一步是查看拉动process.env 是否是一种良好的安全做法。如果存在，我确实希望看到一些其他可能更好的方法的答案。
【讨论】：
dom-ready 上没有问题。挂钩dom-ready 只是为了向渲染器发出事件是矫枉过正（IMO）。看看我的回答【参考方案2】：
在回答您的问题之前，请查看您发送给渲染器的消息（如果您想要将应用程序版本发送到渲染进程），可以使用app.getVersion 完成。在您的主流程中，您必须使用app.setVersion("1.0") 设置应用程序版本，然后在您的渲染流程中您必须这样做
const remote: app = require("electron");
app.getVersion();
对于您的实际问题 mainWindow.createWindow() 需要返回 BrowserWindow 的实例（查看您的代码，您没有返回它，而且您也没有阅读您在 mainWindow.js 上设置的 win 属性对象）。如果您想在问题中坚持使用当前代码，则必须这样做
mainWindow.win.webContents.send(...)
或者你应该这样做
mainWindow.js
// Modules
const BrowserWindow = require('electron')
// export mainWindow
exports.createWindow = () =>
// BrowserWindow options
// https://electronjs.org/docs/api/browser-window#new-browserwindowoptions
const win = new BrowserWindow(
minWidth: 400,
minHeight: 400,
frame: false,
webPreferences:
nodeIntegration: true,
backgroundThrottling: false
)
// Devtools
win.webContents.openDevTools()
// Load main window content
win.loadURL(`file://$__dirname/index.html`)
// Handle window closed
win.on('closed', () =>
this.win = null
)
return win;
main.js
const app, ipcMain, Menu = require('electron')
const appVersion = process.env.npm_package_version
const mainWindow = require('./renderer/mainWindow')
app.on('ready', () =>
const win = mainWindow.createWindow(),
console.log(`Trying to send app version to renderer: $appVersion`),
win.webContents.send('app-version', appVersion),
Menu.setApplicationMenu(mainMenu)
)
【讨论】：
编辑了我的问题以解决答案。目前这不起作用。 @Gʀɪᴍ 在 const 声明中缺少初始化程序的原因是因为您没有从mainWindow.createWindow() 返回任何值
复制mainWindow.js和main.js
您编辑的问题在那里有答案。 win is not defined（这意味着您没有将 win 设置为 BrowserWindow 的实例）
我复制了你的内容，将this.win = new BrowserWindow 更改为const win = new BrowserWindow 并添加了return以上是关于为啥我的 ipcMain 没有发送到 Electron 中的 ipcRenderer？的主要内容，如果未能解决你的问题，请参考以下文章
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