导入anuglar2/形成导致“;无法读取属性'注释'“未定义”;

Importing anuglar2/forms causing "Cannot read property 'annotations' of undefined"

本文关键字：未定义 读取 属性 注释 导入 anuglar2      更新时间：2023-09-26

我正在尝试创建中所述的简单表单http://angularjs.blogspot.no/2015/03/forms-in-angular-2.html，但是当我添加时

import {forms, required} from 'angular2/forms';

与发生碰撞

TypeError: Cannot read property 'annotations' of undefined
TypeError: Cannot read property 'annotations' of undefined
    at ReflectionCapabilities.System.register.execute.$__export.annotations (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/reflection/reflection_capabilities.es6!eval:81:40)
    at Reflector.System.register.execute.$__export.annotations (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/reflection/reflector.es6!eval:81:50)
    at DirectiveMetadataReader.System.register.execute.$__export.read (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/directive_metadata_reader.es6!eval:31:41)
    at eval (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:127:35)
    at Array.map (native)
    at Function.System.register.execute.$__export.map (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/facade/collection.es6!eval:172:26)
    at Compiler.System.register.execute.$__export.createSteps (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:126:43)
    at Compiler.System.register.execute.$__export._compileTemplate (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:164:53)
    at eval (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:154:29)
    at Zone.run (http://localhost:9090/node_modules/zone.js/zone.js:87:19)
-----async gap-----
Error
    at Function.System.register.execute.$__export.then (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/facade/async.es6!eval:35:28)
    at Compiler.System.register.execute.$__export._compile (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:153:42)
    at Compiler.System.register.execute.$__export.compile (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/compiler/compiler.es6!eval:134:34)
    at eval (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:73:23)
    at Function.System.register.execute.$__export.apply (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/facade/lang.es6!eval:317:23)
-----async gap-----
Error
    at _AsyncInjectorStrategy.System.register.execute._AsyncInjectorStrategy.instantiate (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/di/injector.es6!eval:297:17)
    at Injector.System.register.execute.$__export._getByKey (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/di/injector.es6!eval:138:33)
    at Injector.System.register.execute.$__export.asyncGet (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/di/injector.es6!eval:112:25)
    at eval (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:113:39)
-----async gap-----
Error
    at VmTurnZone.System.register.execute.$__export._createInnerZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/zone/vm_turn_zone.es6!eval:61:45)
    at new VmTurnZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/zone/vm_turn_zone.es6!eval:29:34)
    at _createVmZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:101:16)
    at bootstrap (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:110:16)
    at y.main (http://localhost:9090/app.js!eval:10:12)
    at http://localhost:9090/?:42:21
-----async gap-----
Error
    at VmTurnZone.System.register.execute.$__export._createInnerZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/zone/vm_turn_zone.es6!eval:61:25)
    at new VmTurnZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/zone/vm_turn_zone.es6!eval:29:34)
    at _createVmZone (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:101:16)
    at bootstrap (http://localhost:9090/node_modules/angular/dist/js/prod/es6/angular2/src/core/application.es6!eval:110:16)
    at y.main (http://localhost:9090/app.js!eval:10:12)
    at http://localhost:9090/?:42:21

我不明白那个错误消息是什么意思，也找不到表单指令定义在哪里。

更新："undefined"实际上是一个"forms"指令，在angular2/modules/angular2/src/forms中似乎真的缺少它。然后DirectiveMetadataReader将"未定义"进一步传递给反射器，最终导致异常。如果能签入Template，那就太好了。

Victor博客中的示例似乎与您使用的版本不匹配（当时API变化太快）。但现在测试版已经发布了（这意味着没有更多的突破性变化），所以我创建了一个尽可能接近功能的工作示例：

Angular 2 Beta

import {Component} from 'angular2/core'
import {ControlGroup, FormBuilder, Validators} from 'angular2/common'
...

http://plnkr.co/edit/ae1WEgQJWPMdEgoweMGd?p=preview只是为了检查它走了多远（够远了！）。

来自Angular版本：2.0.0-rc.1

所有使用angular2的导入都需要更改为@angular

import {Component} from '@angular/core'
import {ControlGroup, FormBuilder, Validators} from '@angular/common';

有关更多进口清单，请参阅此处：-

  • 更新到angular2 RC的所有导入的列表
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