Question

我必须遗漏一些完全明显的东西，我根本不理解错误。

错误讯息：

wwwroot/app/comments/commentList.ts(25,13): error TS2322: Type 'Comment[]' is not assignable to type 'Comment[]'.
Type 'Comment' is not assignable to type 'Comment'.
wwwroot/app/comments/commentList.ts(25,13): error TS2322: Type 'Comment[]' is not assignable to type 'Comment[]'.
Type 'Comment' is not assignable to type 'Comment'.
Property 'ID' is missing in type 'Comment'.

组件：

@Component({
   selector: 'blog-comment-list',
   templateUrl: './app/comments/commentList.html'
})
export class CommentList implements OnInit {
    @Input() contentItemID: number;
    private comments: Comment[];

    constructor(private sessionService: SessionService, private blogService: BlogService) {

    }

    ngOnInit() {


        this.blogService.GetCommentsForContentItem(this.contentItemID).subscribe(x => {
            this.comments = x;  // *** BUILD ERROR HERE ***
        });
    }

}

服务：

GetCommentsForContentItem(contentItemID: number): Observable<Comment[]>
{
    let url = this.serviceURL + 'GetCommentsForContentItem?contentItemID=' + contentItemID.toString();
    return this.http.get(this.noCache(url))
        .map(response => this.extractData(response))
        .catch(this.handleError);
}

private extractData(res: Response) {
    if (res.status < 200 || res.status >= 300) {
        throw new Error('Bad response status: ' + res.status);
    }
    let body = res.json();
    return body || [];
}

private handleError(error: any) {
    let errorMsg = error.message || 'Server errorx';
    console.error(errorMsg);
    return Observable.throw(errorMsg);
}

private noCache(url: string): string
{
    if (url === null || typeof (url) === 'undefined')
        return null;

    if (url.slice(-1) === '/')
        url = url.slice(0, -1);

    let connector = url.includes('?') ? '&' : '?';

    url = url + connector + 'noCache=' + (Math.random().toString().replace('.', ''));
    return url;
}

型号：

export class Comment {
    public ID: number;
    // more properties
}

的package.json

{
  "version": "1.0.0",
  "name": "samsblog",
  "private": true,
  "dependencies": {
    "@angular/common": "2.0.0-rc.1",
    "@angular/compiler": "2.0.0-rc.1",
    "@angular/core": "2.0.0-rc.1",
    "@angular/http": "2.0.0-rc.1",
    "@angular/platform-browser": "2.0.0-rc.1",
    "@angular/platform-browser-dynamic": "2.0.0-rc.1",
    "@angular/router": "2.0.0-rc.1",
    "@angular/router-deprecated": "2.0.0-rc.1",
    "@angular/upgrade": "2.0.0-rc.1",
    "bootstrap": "^3.3.6",
    "es6-shim": "^0.35.0",
    "reflect-metadata": "^0.1.3",
    "rxjs": "5.0.0-beta.6",
    "systemjs": "0.19.27",
    "core-js": "^2.4.0",
    "zone.js": "^0.6.12"
  },
  "devDependencies": {
    "del": "2.2.0",
    "gulp": "^3.9.1",
    "gulp-clean": "^0.3.2",
    "gulp-concat": "^2.6.0",
    "gulp-ignore": "^2.0.1",
    "gulp-minify": "0.0.12",
    "gulp-rename": "^1.2.2",
    "gulp-typescript": "^2.13.4",
    "gulp-uglify": "^1.5.3",
    "gulp-util": "^3.0.7",
    "typescript": "^1.8.10",
    "typings": "^1.0.4"
  }
}

Answer 1

我不完全确定，这只是猜测。

在你正在做的extractData方法中：

return res.json() || []

其中res为angular Response object，根据文档，json() method会返回any。

更重要的是，你的Comment是一个类而不是一个接口，所以你不能只拿一个json并将其作为Comment返回，即使它们之间的属性完全匹配。 / p>

你需要这样做：

private extractData(res: Response) {
    if (res.status < 200 || res.status >= 300) {
        throw new Error('Bad response status: ' + res.status);
    }

    return (res.json() || []).map(commentJson => new Comment(commentJson));
}

interface CommentJson {
    ID: number;
    // more properties
}

export class Comment {
    public ID: number;
    // more properties

    constructor(json: CommentJson) {
        this.ID = json.ID;
    }
}

同样，不确定这是你的问题，但是根据您发布的代码，您似乎遇到了这些问题。

错误TS2322：类型'Comment []'不能分配给'Comment []'

1 个答案: