错误类型错误：无法读取未定义的属性（读取“nativeElement”）

Question

我最近将 package.json 中的依赖项升级到最新版本。依赖项已过时至少 2 年或更长时间。我正在处理的网站显示各种类型的图形和图表，并且在升级到 package.json 之前工作正常。这会是什么原因呢？

这是更新后的 package.json

{
  "name": "pipeline-viewer",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^12.0.0",
    "@angular/cdk": "^12.0.0",
    "@angular/common": "^12.0.0",
    "@angular/compiler": "^12.0.0",
    "@angular/core": "^12.0.0",
    "@angular/flex-layout": "^12.0.0-beta.35",
    "@angular/forms": "^12.0.0",
    "@angular/material": "^12.0.0",
    "@angular/material-moment-adapter": "^12.0.0",
    "@angular/platform-browser": "^12.0.0",
    "@angular/platform-browser-dynamic": "^12.0.0",
    "@angular/router": "^12.0.0",
    "@wizpanda/super-gif": "0.0.5",
    "angular-plotly.js": "^4.0.4",
    "bootstrap": "^5.1.3", 
    "moment": "^2.29.1",
    "plotly.js": "^2.5.1",
    "rxjs": "^7.4.0",
    "rxjs-compat": "^6.6.7",
    "zone.js": "^0.11.4"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^12.0.0",
    "@angular/cli": "^12.0.0",
    "@angular/compiler-cli": "^12.0.0"
  }
}

这是显示图形和图表的旧 package.json。

{
  "name": "pipeline-viewer",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^7.1.4",
    "@angular/cdk": "^7.3.7",
    "@angular/common": "~7.1.0",
    "@angular/compiler": "~7.1.0",
    "@angular/core": "~7.1.0",
    "@angular/flex-layout": "^7.0.0-beta.24",
    "@angular/forms": "~7.1.0",
    "@angular/material": "^7.3.3",
    "@angular/material-moment-adapter": "^8.1.2",
    "@angular/platform-browser": "~7.1.0",
    "@angular/platform-browser-dynamic": "~7.1.0",
    "@angular/router": "~7.1.0",
    "@wizpanda/super-gif": "0.0.5",
    "angular-plotly.js": "^1.3.2",
    "bootstrap": "^4.2.1",
    "moment": "^2.24.0",
    "plotly.js": "^1.49.0",
    "rxjs": "~6.3.3",
    "rxjs-compat": "^6.3.3",
    "zone.js": "~0.8.26"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.11.0",
    "@angular/cli": "~7.1.3",
    "@angular/compiler-cli": "~7.1.0"
  }
}

Answer 1

它与 Angular +8 中的 viewChild 更改有关

改变

@ViewChild('element') element: ElementRef;

到

@ViewChild('element', {static: true}) element: ElementRef;
// to access your view Child in ngOnInit

ContentChild 也是如此