在以下代码的这一行@ViewChild('myListView') listViewComponent: RadListViewComponent;
我收到此错误消息:
预期 2 个参数,但得到 1.ts(2554( core.d.ts(8054, 47(:一个没有提供"选择"的论据。
由于我是一名新学习者,只是遵循 2017 年的教程,我不知道为什么会发生这种情况以及如何解决它?但是似乎ViewChild()
装饰器的实现发生了变化,尽管我不知道如何调整我的代码来修复它?
import { Component, OnInit, Inject, ViewChild, ChangeDetectorRef } from '@angular/core';
import { View } from 'tns-core-modules/ui/core/view';
import { FavoriteService } from '../services/favorite.service';
import { Dish } from '../shared/dish';
import { ListViewEventData, RadListView } from 'nativescript-ui-listview';
import { RadListViewComponent } from 'nativescript-ui-listview/angular';
import { ObservableArray } from 'tns-core-modules/data/observable-array';
import { DrawerPage } from '../shared/drawer/drawer.page';
import { confirm } from "tns-core-modules/ui/dialogs";
import { Toasty, ToastDuration, ToastPosition } from 'nativescript-toasty';
@Component({
selector: 'app-favorites',
moduleId: module.id,
templateUrl: './favorites.component.html',
styleUrls: ['./favorites.component.css']
})
export class FavoritesComponent extends DrawerPage implements OnInit {
favorites: ObservableArray<Dish>;
errMess: string;
@ViewChild('myListView') listViewComponent: RadListViewComponent;
constructor(private favoriteservice: FavoriteService,
private changeDetectorRef: ChangeDetectorRef,
@Inject('BaseURL') private BaseURL) {
super(changeDetectorRef);
}
ngOnInit() {
this.favoriteservice.getFavorites()
.subscribe(favorites => this.favorites = new ObservableArray (favorites),
errmess => this.errMess = errmess);
}
deleteFavorite(id: number) {
console.log('delete', id);
let options = {
title: "Confirm Delete",
message: 'Do you want to delete Dish '+ id,
okButtonText: "Yes",
cancelButtonText: "No",
neutralButtonText: "Cancel"
};
confirm(options).then((result: boolean) => {
if(result) {
this.favorites = null;
this.favoriteservice.deleteFavorite(id)
.subscribe(favorites => {
//const toast = new Toasty("Deleted Dish "+ id, "short", "bottom" );
//toast.show();
const toasty = new Toasty({ text: "Deleted Dish "+ id })
.setToastDuration(ToastDuration.SHORT)
.setToastPosition(ToastPosition.BOTTOM)
//.setTextColor(new Color('white'))
//.setBackgroundColor('#ff9999')
.show();
this.favorites = new ObservableArray(favorites);
},
errmess => this.errMess = errmess);
}
else {
console.log('Delete cancelled');
}
});
}
public onCellSwiping(args: ListViewEventData) {
var swipeLimits = args.data.swipeLimits;
var currentItemView = args.object;
var currentView;
if(args.data.x > 200) {
}
else if (args.data.x < -200) {
}
}
public onSwipeCellStarted(args: ListViewEventData) {
var swipeLimits = args.data.swipeLimits;
var swipeView = args['object'];
var leftItem = swipeView.getViewById<View>('mark-view');
var rightItem = swipeView.getViewById<View>('delete-view');
swipeLimits.left = leftItem.getMeasuredWidth();
swipeLimits.right = rightItem.getMeasuredWidth();
swipeLimits.threshold = leftItem.getMeasuredWidth()/2;
}
public onSwipeCellFinished(args: ListViewEventData) {
}
public onLeftSwipeClick(args: ListViewEventData) {
console.log('Left swipe click');
this.listViewComponent.listView.notifySwipeToExecuteFinished();
}
public onRightSwipeClick(args: ListViewEventData) {
this.deleteFavorite(args.object.bindingContext.id);
this.listViewComponent.listView.notifySwipeToExecuteFinished();
}
}
如果您使用的是 angular8,则ViewChild()
装饰器已更改:https://angular.io/guide/static-query-migration,因此您缺少static
参数 @ViewChild('myListView', {static: false}) listViewComponent: RadListViewComponent;
在 v8 中,ViewChild 语法已更改 CHANGELOG 说
"核心:在 Angular 版本 8 中,需要所有 @ViewChild 和 @ContentChild查询都有一个"静态"标志,指定是否 查询是"静态"或"动态"。编译器先前对查询进行了排序 自动,但在 8.0 中,开发人员需要明确 指定所需的行为。这是一个临时要求,因为 迁移的一部分;看 https://v8.angular.io/guide/static-query-migration 了解更多详情。
我建议使用 https://github.com/angular/angular/blob/master/CHANGELOG.md 更新