類型為'number'的參數不能賦值給'string'類型的參數

Question

我對打字稿很新，所以請原諒我，如果這是一個菜鳥問題。 我正在使用angular cli制作一個簡單的主細節應用程序。 但是我收到了這個錯誤

argument of type 'number' is not assignable to a parameter of type 'string'

到目前為止，我可以看到它是一個字符串，而不是一個數字，所以我很困惑。

我的代碼：模特

export class Actor {
    lastName: string;
    profession: string;
    bio: string;
    url: string;
    imageUri: string;
    name: string;
    id: string;
    realName: string;
}

服務

import { Injectable } from '@angular/core';
import { Actor } from '../model/actor';
// import { ACTORS } from './mock-actors';
import { Http } from '@angular/http';
import 'rxjs/add/operator/toPromise';

@Injectable()
export class ActorService {
    private actorsUrl = '/app/persons.json';
    constructor(private http: Http) { }
    getActors(): Promise<Actor[]> {
        return this.http.get(this.actorsUrl)
            .toPromise().then(response => <Actor[]>response.json().personList)
            /*.toPromise().then(response => response.json().personList as Actor[])*/
            .catch(this.handleError);
    }

    private handleError(error: any): Promise<any> {
        console.error('Error: ', error);
        return Promise.reject(error.message);
    }
    getActor(name: string): Promise<Actor> {
        return this.getActors().then(actors => actors.find(actor => actor.name === name));
    }
}

零件

import { Component, OnInit } from '@angular/core';
import { Actor } from '../../model/actor';
import { ActivatedRoute, ParamMap } from '@angular/router';
import { Location } from '@angular/common';
import { ActorService } from '../../service/actor.service';
import 'rxjs/add/operator/switchMap';

@Component({
    /*selector: 'actor-detail',*/
    templateUrl: './detail-index.component.html'
})
export class ActorDetailComponent implements OnInit{
    actor: Actor;
    constructor(
        private actorService: ActorService,
        private route: ActivatedRoute,
        private location: Location
    ) {}
    ngOnInit(): void {
        this.route.paramMap.switchMap((params: ParamMap) =>
        this.actorService.getActor(+params.get('name'))) // argument of type 'number' is not assignable to a parameter of type 'string'
            .subscribe(hero => this.actor = actor);
    }
    goBack(): void {
        this.location.back();
    }
}

我也得到以下錯誤

cannot find name 'actor' in the component file

Answer 1

您的方法需要一個string作為參數，將其更改為

 this.actorService.getActor(params.get('name'))).subscribe(hero => this.actor = actor);

也在ts中聲明一個變量

actor : any;

Answer 2

因為我可以看到它是一個字符串，而不是一個數字

+params.get('name')是一個數字，因為JavaScript中的一元+ 將其操作數轉換為數字 。