Question

我做错了什么？

import {bootstrap, Component} from 'angular2/angular2'

@Component({
  selector: 'conf-talks',
  template: `<div *ngFor="talk of talks">
     {{talk.title}} by {{talk.speaker}}
     <p>{{talk.description}}
   </div>`
})
class ConfTalks {
  talks = [ {title: 't1', speaker: 'Brian', description: 'talk 1'},
            {title: 't2', speaker: 'Julie', description: 'talk 2'}];
}
@Component({
  selector: 'my-app',
  directives: [ConfTalks],
  template: '<conf-talks></conf-talks>'
})
class App {}
bootstrap(App, [])

错误是

EXCEPTION: Template parse errors:
Can't bind to 'ngFor' since it isn't a known native property
("<div [ERROR ->]*ngFor="talk of talks">

Answer 1

我在let前面错过了talk：

<div *ngFor="let talk of talks">

请注意，#...使用let来声明NgFor等结构指令中的局部变量是不推荐使用的。请改用<div *ngFor="#talk of talks">。 <div *ngFor="let talk of talks">现在变为#

原始答案：

我在talk前面错过了<div *ngFor="#talk of talks">：

很容易忘记you forgot that # again。我希望Angular异常错误消息代之以：
public void signDetached(String inputFilePath, String outputFilePath, String signatureImagePath, Sign signProperties) { OutputStream outputStream = null; InputStream inputStream = null; PDDocument document = null; InputStream signImageStream = null; try { setTsaClient(null); document = PDDocument.load(inputFilePath); // create signature dictionary PDSignature signature = new PDSignature(); signature.setFilter(PDSignature.FILTER_ADOBE_PPKLITE); signature.setSubFilter(PDSignature.SUBFILTER_ADBE_PKCS7_DETACHED); signature.setName("VANDUC1102"); signature.setLocation(null); String displayName = "Hello World, Document signed by VANDUC1102"; String reason = reasonText+ " " + displayName; signature.setReason(reason); // the signing date, needed for valid signature signature.setSignDate(Calendar.getInstance()); int signatureInPage = signProperties.getPageNumber() + 1; signImageStream = new FileInputStream(new File(signatureImagePath)); PDVisibleSignDesigner visibleSig = new PDVisibleSignDesigner(inputFilePath, signImageStream, signatureInPage); float xAxis = convertPixel2Point(signProperties.getX()) ; float yAxis = convertPixel2Point(signProperties.getY()); float signImageHeight = convertPixel2Point(signImageHeight); float signImageWidth = convertPixel2Point(signImageWidth); visibleSig.xAxis(xAxis) .yAxis(yAxis) .zoom(0) .signatureFieldName("Signature") .height(signImageHeight) .width(signImageWidth); PDVisibleSigProperties signatureProperties = new PDVisibleSigProperties(); signatureProperties.signerName(eiUser.getName()) .signerLocation(null) .signatureReason(reason) .preferredSize(0) .page(signProperties.getPageNumber()) .visualSignEnabled(true) .setPdVisibleSignature(visibleSig) .buildSignature(); // register signature dictionary and sign interface SignatureOptions signatureOptions = new SignatureOptions(); signatureOptions.setVisualSignature(signatureProperties); signatureOptions.setPage(signatureInPage); document.addSignature(signature, this, signatureOptions); File outputFile = new File(outputFilePath); outputStream = new FileOutputStream(outputFile); inputStream = new FileInputStream(inputFilePath); IOUtils.copyStream(inputStream, outputStream); document.saveIncremental(inputStream, outputStream); outputStream.flush(); } catch (COSVisitorException | SignatureException | IOException ex) { log.error("signDetached ", ex); } finally { IOUtils.closeStream(outputStream); IOUtils.closeStream(inputStream); IOUtils.closeStream(signImageStream); IOUtils.closeStream(document); } } private float convertPixel2Point(float pixel){ return pixel * (float) 72/96; }。

Answer 2

导致OP错误的另一个错误可能是使用in：

<div *ngFor="let talk in talks">

您应该使用of代替：

<div *ngFor="let talk of talks">

Answer 3

This Statement used in Angular2 Beta version.....

Hereafter use let instead of #

let keyword is used to declare local variable

Answer 4

就我而言，这是一封小写字母f。我正在分享这个答案，因为这是谷歌的第一个结果

请务必撰写 *ngFor

Answer 5

就我而言，我犯了从文档中复制*ng-for=的错误。

https://angular.io/guide/user-input

如果我错了，请纠正我。但似乎*ng-for=已更改为*ngFor=

Answer 6

对我来说，长话短说，我无意中降级为角度-β-16。

let ...语法仅在2.0.0-beta.17 +

中有效

如果您对此版本以下的任何内容尝试let语法。您将生成此错误。

升级到angular-beta-17或使用#item in items语法。

Answer 7

仅在我遇到相同错误并且原因是在迭代器中使用而不是而不是 of 时，才涉及另一种情况

错误的方法let file in files

正确的方法let file of files

Answer 8

在angular 7中，通过将以下行添加到.module.ts文件中来解决此问题：

import { CommonModule } from '@angular/common'; imports: [CommonModule]

Answer 9

您应该使用let关键字作为声明局部变量例如* ngFor =“让我们谈论话题”

Answer 10

使用此

<div *ngFor="let talk of talks> 
   {{talk.title}} 
   {{talk.speaker}}
   <p>{{talk.description}} 
</div>

您需要指定变量以遍历对象数组

Answer 11

在我的例子中，= 和 " 之间不应该有空格，例如错误的 *ngFor = "let talk of talk" 右：*ngFor="让我们谈谈"

Answer 12

我忘了用“ @Input”（注！）为组件添加注释。

book-list.component.html （违规代码）：

<app-book-item
  *ngFor="let book of book$ | async"
  [book]="book">  <-- Can't bind to 'book' since it isn't a known property of 'app-book-item'
</app-book-item>

book-item.component.ts 的正确版本：

import { Component, OnInit, Input } from '@angular/core';

import { Book } from '../model/book';
import { BookService } from '../services/book.service';

@Component({
  selector: 'app-book-item',
  templateUrl: './book-item.component.html',
  styleUrls: ['./book-item.component.css']
})
export class BookItemComponent implements OnInit {

  @Input()
  public book: Book;

  constructor(private bookService: BookService)  { }

  ngOnInit() {}

}

Answer 13

也不要在这种情况下尝试使用纯TypeScript ...我想更符合for的用法，并使用*ngFor="const filter of filters"并得到ngFor未知属性错误。只是用let代替const即可。

正如@ alexander-abakumov所说，of被in取代。

Answer 14

就我而言，使用* ngFor包含组件的模块导致此错误，未包含在app.module.ts中。将其包含在imports数组中对我来说解决了这个问题。

例外：无法绑定到'ngFor'，因为它不是已知的本机属性

14 个答案: