小编use*_*978的帖子

我刚开始研究系统调用.我想知道在进行系统调用时导致开销的原因.

例如,如果我们考虑getpid(),当对getpid()进行系统调用时,我的猜测是如果控件当前在子进程中,则必须进行上下文切换以进入父进程以获取pid .这会导致开销吗？

此外,当调用getpid()时,将在用户空间边界上进行一些元数据传输并进入和退出内核.那么用户空间和内核之间的常量切换是否也会导致一些开销？

我尝试使用该命令将我的应用程序从Angular 2.4.10升级到4.0.0

"npm install @angular/common@next @angular/compiler@next @angular/compiler-cli@next @angular/core@next @angular/forms@next @angular/http@next @angular/platform-browser@next @angular/platform-browser-dynamic@next @angular/platform-server@next @angular/router@next @angular/animations@next --save". 

虽然在"npm install"期间没有错误,但在"npm run build"期间我收到了以下错误.我按照changelog中的指示将"lib"添加到compilerOptions.

ERROR in [default]
File '/node_modules/bootstrap-loader/loader.js' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts'.

ERROR in [default]
File '/node_modules/core-js/es6/index.js' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts'.

ERROR in [default]
File '/node_modules/fullcalendar/dist/fullcalendar.min.js' has unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts'.

ERROR in [default]
File '/node_modules/hammerjs/hammer.js' has unsupported extension. The only supported extensions …

目前,该应用程序是在Angular 2.0.0上.为了与Angular 4兼容,需要更改哪些包或依赖项？到目前为止,我改变了以下内容,

"dependencies": {
"@angular/common": "4.0.0",
"@angular/compiler": "4.0.0",
"@angular/core": "4.0.0",
"@angular/forms": "4.0.0",
"@angular/http": "4.0.0",
"@angular/platform-browser": "4.0.0",
"@angular/platform-browser-dynamic": "4.0.0",
"@angular/router": "4.0.0",
"@angular/router-deprecated": "2.0.0-rc.2",
"@angular/upgrade": "4.0.0",
"angular2-toaster": "2.0.0",
"rxjs": "^5.0.1",
"typescript": "^2.1.5",
"zone.js": "^0.8.4"
}

是否还有其他需要更改的包/依赖项？

我应该更改tsconfig.json吗？

{


 "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "lib": [
      "es5",
      "es2015",
      "es2017",
      "dom",
      "scripthost"
    ],
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "sourceMap": true,
    "noEmitHelpers": true,
    "allowNonTsExtensions" : true
  },
  "exclude": [
    "node_modules",
    "typings/main.d.ts",
    "typings/main"
  ],
  "filesGlob": [
    "./src/**/*.ts",
    "./test/**/*.ts",
    "!./node_modules/**/*.ts",
    "src/custom_typings.d.ts",
    "typings/browser.d.ts"
  ],
  "awesomeTypescriptLoaderOptions": {
    "resolveGlobs": …

ng2-auto-complete通过遵循此示例，我已经实现了Angular 2 组件。您也可以从这里访问它。

我面临的问题是，我的来源是对象形式，id其中一个是字段。并按照组件的实现示例，id在下拉菜单中的括号中显示。有没有办法id在下拉菜单中不显示？

这是我的自动完成组件的HTML代码：

<input ng2-auto-complete id="inputEvent" class="form-control" [(ngModel)]="model" ngModel
     name="event" #event="ngModel" [source]="items" display-property-name="name" (valueChanged)="onSelect($event)"/>

这是我得到的：