Angular PrimeNG侧栏清除primeNG消息.为什么

侧边栏菜单有一个名为p-messages的组件，如果你判断该元素，你会注意到，当你关闭时，p-sidebar的内容会被销毁.

当您重新打开侧边栏时，数据保持不变，但消息被销毁.

我认为p-messages组件只会显示数组引用正在改变，这可能是由于组件内部的*ngFor与trackBy，所以我们需要重置内存中的每个数组元素引用，这样我们就可以欺骗p-messages，让它认为列表中有新的消息，为此我们可以使用对象解构！我会在打开侧边栏时这样做(onShowNotificationSideBar)

onShowNotificationSideBar() {
    this.notificationSideBarVisible = true;
    this.messages = [...this.messages.map(x => ({...x}))]; // <- creates new references for the array and its contents!
}

完整代码

import { Component } from '@angular/core';
import { Message, MessageService } from 'primeng/api';

@Component({
  selector: 'sidebar-basic-demo',
  templateUrl: './sidebar-basic-demo.HTML',
  providers: [MessageService],
})
export class SidebarBasicDemo {
  title = 'WECO';
  notificationSideBarVisible = false;

  constructor(private messageService: MessageService) {
    messageService.messageObserver.subscribe((m: Message | Message[]) => {
      if (!Array.isArray(m)) {
        this.messages.push(m);
      }
      this.messages = [...this.messages];
    });
  }

  onShowNotificationSideBar() {
    this.notificationSideBarVisible = true;
    this.messages = [...this.messages.map(x => ({...x}))];
  }

  count = 0;

  messages: Message[] = [
    // { severity: 'success', summary: 'Success', detail: 'Message Content' },
    // { severity: 'info', summary: 'Info', detail: 'Message Content' },
    // { severity: 'warn', summary: 'Warning', detail: 'Message Content' },
    // { severity: 'error', summary: 'Error', detail: 'Message Content' }
  ];

  longSentence =
    'Let’s end all this nonsense about how long sentences = run-on sentences. You can have a six-word run-on sentence (“I went shopping I ate donuts.”), while most of the sentences below are much, much longer than that and are not run-ons'; //'And let’s end all this nonsense about how long sentences = run-on sentences. You can have a six-word run-on sentence (“I went shopping I ate donuts.”), while most of the sentences below are much, much longer than that and are not run-ons (except for a few examples like Jose Saramago).  But whether the sentence is grammatically correct isn’t nearly as important as whether the sentence is fun or beautiful.'

  showWarn() {
    let detail = 'User Deleted a Weco Rule';
    if (this.count++ % 5 === 0) detail = this.longSentence;
    this.messageService.add({
      severity: 'warn',
      summary: 'User Action',
      detail: detail,
    });
  }

  showSuccess() {
    let detail = 'Weco Rule 123 Saved';
    if (this.count++ % 5 === 0) detail = this.longSentence;
    this.messageService.add({
      severity: 'success',
      summary: 'Service Call',
      detail: detail,
    });
  }

  showError() {
    let detail = 'api-call:get-factories returned 404';
    if (this.count++ % 5 === 0) detail = this.longSentence;
    this.messageService.add({
      severity: 'error',
      summary: 'Service Call',
      detail: detail,
    });
  }
}

HTML

<div class="main">
  <button type="button" (click)="onShowNotificationSideBar()" label="Show">
    show sidebar
  </button>
  <p-sidebar
    [(visible)]="notificationSideBarVisible"
    position="right"
    [style]="{width:'50em'}"
  >
    <button
      type="button"
      pButton
      pRipple
      (click)="showSuccess()"
      label="S"
      class="p-button-success"
    >
      success
    </button>
    <button
      type="button"
      pButton
      pRipple
      (click)="showWarn()"
      label="W"
      class="p-button-warning"
    >
      warn
    </button>
    <button
      type="button"
      pButton
      pRipple
      (click)="showError()"
      label="E"
      class="p-button-danger"
    >
      error
    </button>
    <h3>Messages</h3>
    <h5>{{messages}}</h5>
    <p-messages [(value)]="messages" [enableService]="false"></p-messages>
  </p-sidebar>
  <p-toast position="center"></p-toast>
</div>

Stackblitz Demo