Angular 在 canDeactivate Guard 服务中使用模态对话框进行未提交的更改(表单脏)

Question

在我的 Angular 4 应用程序中，我有一些带有表单的组件，如下所示:

export class MyComponent implements OnInit, FormComponent {

  form: FormGroup;

  ngOnInit() {
    this.form = new FormGroup({...});
  }

他们使用 Guard 服务来防止未提交的更改丢失，因此如果用户尝试在它要求确认之前更改路线:

import { CanDeactivate } from '@angular/router';
import { FormGroup } from '@angular/forms';

export interface FormComponent {
  form: FormGroup;
}

export class UnsavedChangesGuardService implements CanDeactivate<FormComponent> {
  canDeactivate(component: FormComponent) {
    if (component.form.dirty) {
      return confirm(
        'The form has not been submitted yet, do you really want to leave page?'
      );
    }

    return true;
  }
}

这是使用一个简单的 confirm(...) 对话框，它工作得很好。

但是我想用更花哨的模式对话框替换这个简单的对话框，例如使用 ngx-bootstrap Modal .

我怎样才能使用模态来实现相同的结果？

Answer 1

我用 ngx-bootstrap Modals 解决了它和 RxJs Subjects .

首先我创建了一个模态组件:

import { Component } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { BsModalRef } from 'ngx-bootstrap';

@Component({
  selector: 'app-confirm-leave',
  templateUrl: './confirm-leave.component.html',
  styleUrls: ['./confirm-leave.component.scss']
})
export class ConfirmLeaveComponent {

  subject: Subject<boolean>;

  constructor(public bsModalRef: BsModalRef) { }

  action(value: boolean) {
    this.bsModalRef.hide();
    this.subject.next(value);
    this.subject.complete();
  }
}

这是模板:

<div class="modal-header modal-block-primary">
  <button type="button" class="close" (click)="bsModalRef.hide()">
    <span aria-hidden="true">&times;</span><span class="sr-only">Close</span>
  </button>
  <h4 class="modal-title">Are you sure?</h4>
</div>
<div class="modal-body clearfix">
  <div class="modal-icon">
    <i class="fa fa-question-circle"></i>
  </div>
  <div class="modal-text">
    <p>The form has not been submitted yet, do you really want to leave page?</p>
  </div>
</div>
<div class="modal-footer">
  <button class="btn btn-default" (click)="action(false)">No</button>
  <button class="btn btn-primary right" (click)="action(true)">Yes</button>
</div>

然后我用一个 Subject 修改了我的守卫，现在它看起来像这样:

import { CanDeactivate } from '@angular/router';
import { FormGroup } from '@angular/forms';
import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { BsModalService } from 'ngx-bootstrap';

import { ConfirmLeaveComponent } from '.....';

export interface FormComponent {
  form: FormGroup;
}

@Injectable()
export class UnsavedChangesGuardService implements CanDeactivate<FormComponent> {

  constructor(private modalService: BsModalService) {}

  canDeactivate(component: FormComponent) {
    if (component.form.dirty) {
      const subject = new Subject<boolean>();

      const modal = this.modalService.show(ConfirmLeaveComponent, {'class': 'modal-dialog-primary'});
      modal.content.subject = subject;

      return subject.asObservable();
    }

    return true;
  }
}

在 app.module.ts 文件中，转到 @NgModule 部分并将 ConfirmLeaveComponent 组件添加到 entryComponents。

@NgModule({
  entryComponents: [
    ConfirmLeaveComponent,
  ]
})