Question

我正在尝试从url获取查询参数（使用Angular 5）：

import { Component, OnInit, OnDestroy } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';

@Component({
    selector: 'app-shop',
    templateUrl: './shop.component.html'
})

export class ShopComponent implements OnInit {
    constructor(private route: ActivatedRoute, private router: Router) { }

    ngOnInit() {
        private sub: any;

        private keyword: string;

        this.sub = this.route.queryParams.subscribe(params => {
            this.keyword = params['keyword'] || null;
        });

        console.log(this.keyword);
    }

    ngOnDestroy() {
        this.sub.unsubscribe();
    }
}

我在控制台日志中收到以下错误：

shop.component.ts:18未捕获的TypeError：无法读取属性 'queryParams'未定义

Answer 1

尝试删除this.sub =访问路由。您也可以尝试通过dot：

加入查询参数

this.route.queryParams.subscribe(params => {
  this.keyword = params.keyword || null;
});

Answer 2

事实证明，我已将ngOnInit()变量设置在导致错误的@RequestMapping(method=RequestMethod.POST, value="/provinces") public void addProvince(@RequestBody Province province) { provinceService.addProvince(province); }内。呵呵...！

无法读取未定义的属性'queryParams'

2 个答案: