电子IPCMain不能访问变量

Question

我有一个带有main.js文件的电子应用程序，它是用一种更oo格式编写的。当我从呈现过程发送请求时，它就会到达。问题是，当它试图为一个对象调用一个方法时，它声明该对象是未定义的。

const { app, BrowserWindow, Menu, shell, dialog, session, ipcMain, webContents } = require('electron')

class GUI extends BrowserWindow {
    /**
     * Generates a window
     * @param {number} width - The initial width of the window. Default 800
     * @param {number} height - The initial height of the window. Default 600
     * @param {number} minWidth - The minimum width the window can possibly be. Default 800
     * @param {number} minHeight - The minimum height the window can possibly be. Default 600
     * @param {string} backgroundColor - The background colour of the window. Default #FFF
     * @param {string} icon - The path to the icon. Default null
     * @param {string} indexFile - The path to the index file to be loaded. Default null
     * @param {Electron.Menu} menu - The menu that should be displayed. Default null
     */
    constructor(width = 800, height = 600, minWidth = 800, minHeight = 600, backgroundColor = '#FFF', icon = null, indexFile = null, menu = null){
        super({
            width: width,
            height: height,
            minWidth: minWidth,
            minHeight: minHeight,
            icon: icon,
            backgroundColor: backgroundColor,
            frame: false,
            webPreferences: {
                nodeIntegration: true,
                enableRemoteModule: true
            }
        })
        this.fullscreen = false
        this.loadFile(indexFile)
        this.webContents.openDevTools()
        Menu.setApplicationMenu(menu)
        
        
        
    }//Constructor
    closeWin(){
        if(this.webContents.isDevToolsOpened == true){
            this.webContents.closeDevTools()
        }
        this.close()
    }//Close
    minimizeWin(){
        this.minimize()
    }
}

//Called when electron has finished initialising
app.on('ready', () => {
    let mainWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png', 'index.html')
})
//Quit when all windows are closed except on macOS
app.on('window-all-closed', () => {
    if (process.platform !== 'darwin'){
        app.quit()
    }
})
ipcMain.on('windowControl', (event, arg) => {
    console.log(arg)
    // var request = JSON.parse(arg)
    var request = arg
    console.log(request)
    console.log(request.window)
    if (request.window == 'mainWindow'){
        if (request.func == 'openPreferences') {
            let preferencesWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png','./html/preferences.html')
        }
        if (request.func == 'close'){
            mainWindow.closeWin()
        }
        if (request.func == 'min'){
            mainWindow.minimizeWin()
        }
        
    } 
    if (request.window == 'app' && request.func == 'exit' && process.platform !== 'darwin'){
        app.quit()
    }
})

单击“关闭”按钮时遇到的错误：

 A JavaScript error occurred in the main process
Uncaught Exception: iN
ReferenceError: mainWindow is not defined
at IpcMainImpl.<anonymous>
(C:\Users\computronics\source\repos\DC-Model-Railway-Controller\source\desktop
client\main,js:111:13)
at IpcMainImpl.emit (events.js:223:5)
at WebContents.< anonymous> (electron/js2c/browser_init.js:173:8161)
at WebContents.emit (events.js:223:5)

我的目标是从呈现过程向主进程发送请求，并执行这些请求。这些请求包括创建和关闭窗口。最小化窗口和其他请求。

从呈现过程发送的示例消息：

{window:'mainWindow', func:'close'}

其他信息

Nodejs: 12.14.1
Chrome: 83.0.4103.122
Electron: 9,1.2
V8: 8,3.110,13-electron.0
OS: Windows_NT x64 10,.0.18362

如有任何帮助，将不胜感激。

Answer 1

app.on('ready', () => {
    let mainWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png', 'index.html')
})

在匿名侦听器函数中定义变量mainWindow。尝试将变量设置为全局变量，如下所示：

var mainWindow;
app.on('ready', () => {
    mainWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png', 'index.html')
})

另一种可能的解决办法是：

if (request.window == 'mainWindow'){
    if (request.func == 'openPreferences') {
        let preferencesWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png','./html/preferences.html')
    }
    if (request.func == 'close'){
        mainWindow.closeWin()
    }
    if (request.func == 'min'){
        mainWindow.minimizeWin()
    }
        
}

将mainWindow替换为request.window

if (request.window == 'mainWindow'){
        if (request.func == 'openPreferences') {
            let preferencesWindow = new GUI(800,600,800,600,'#323233','./assets/logos/logo.png','./html/preferences.html')
        }
        if (request.func == 'close'){
            request.window.closeWin()
        }
        if (request.func == 'min'){
            request.window.minimizeWin()
        }
            
    }