使用指令 Angular 2 更改输入的 ngModel 值

Question

我无法理解如何使用指令访问和更改输入 ngModel 值。问题的结果是，当我 select 所需地址时，模型的地址值不会更新...它只是设置为我实际输入到输入中的内容，而不是输入的最终值。

我输入“830”：

I select '8300 Fauntleroy Way Southwest, Seattle, WA, United States':

结果值：

{
  address: '830'
}

期望值：

{
  address: '8300 Fauntleroy Way Southwest, Seattle, WA, United States'
}

在 AngularJS 中我可以这样做：

(function() {
  'use strict';

  angular
  .module('casemanagerApp')
  .directive('googleplace', googleplace);

  function googleplace() {

    var directive = {
      require: 'ngModel',
      link: link
    };

    return directive;

    function link(scope, element, attrs, model) {
      var options = {
        types: [],
        componentRestrictions: {}
      };
      scope.gPlace = new google.maps.places.Autocomplete(element[0], options); // jshint ignore:line

      google.maps.event.addListener(scope.gPlace, 'place_changed', function() { // jshint ignore:line
        scope.$apply(function() {
          model.$setViewValue(element.val());
        });
      });
    }
  }

})();

但现在我正在尝试转换它 Angular2，我有点卡住了。到目前为止，这是我对转换的了解：

/// <reference path="../../../../typings/browser/ambient/googlemaps/index.d.ts"/>

import { Directive, ElementRef, OnInit } from '@angular/core';

@Directive({
  selector: '[google-places]'
})
export class GooglePlaces implements OnInit {

  constructor(private _el: ElementRef) { }

  ngOnInit() {
    let gPlace = new google.maps.places.Autocomplete(this._el.nativeElement);
    google.maps.event.addListener(gPlace, 'place_changed', () => console.log(this._el.nativeElement));
  }

}

用法：

<input type="text"
       ngControl="address"
       placeholder="Enter a location"
       [(ngModel)]="subject.address"
       #address="ngForm"
       google-places
       required>

问题的核心是我不明白如何在 Angular 2 中做相当于 model.$setViewValue(element.val()); 的事情。

如有任何帮助，我们将不胜感激。

Plunker

Answer 1

我会注入与您的输入相关联的 ControlValueAccessor。这是一个示例：

@Directive({
  selector: '[test]'
})
export class TestDirective {
  constructor(@Inject(NG_VALUE_ACCESSOR) private valueAccessor:ControlValueAccessor) {
    setTimeout(() => {
      this.valueAccessor[0].writeValue('test');
    }, 1000);
  }
}

例如，请参阅此 plunkr：https://plnkr.co/edit/owhBHdBncAxlzwJ8xkfq?p=preview。

Answer 2

我最终让它起作用了，尽管我不明白为什么它起作用，因为我没有将 ngModelChange 绑定到元素...但它起作用了。

指令：

/// <reference path="../../../../typings/browser/ambient/googlemaps/index.d.ts"/>

import { Directive, ElementRef, Output, EventEmitter, OnInit, NgZone } from '@angular/core';

@Directive({
  selector: '[google-places]'
})
export class GooglePlaces implements OnInit {
  @Output() ngModelChange: EventEmitter<any> = new EventEmitter(false);

  options = {
    types: ['address'],
    componentRestrictions: { country: "us" }
  };

  constructor(
    private _el: ElementRef,
    private _ngZone: NgZone) { }

  ngOnInit() {
    let gPlace = new google.maps.places.Autocomplete(this._el.nativeElement, this.options);
    google.maps.event.addListener(gPlace, 'place_changed', () => {
      this._ngZone.run(() =>
        this.ngModelChange.emit(this._el.nativeElement.value));
    });
  }

}

组件模板：

<input type="text"
            class="form-control"
            ngControl="address"
            id="subjectAddress"
            placeholder="Enter a location"
            [(ngModel)]="subject.address"
            #address="ngForm"
            google-places
            required>

Answer 3

这是我用我的日期选择器所做的，可能会有帮助。

//Create a method in your component to change the model
dateChanged(date) {
   this.hero.bday = date;
}

public ngOnInit() {
    //CREATE A REFERERENCE TO YOUR COMPONENT
    var component:CreateEventComponent = this;
    $("#bday").datepicker({
        dateFormat: "dd-mm-yy",
        altFormat: "dd-mm-yy",
        onSelect: function (dateText, datePicker) {
            //UPDATE YOUR MODEL FORM JQUERY CODE.
            component.dateChanged(dateText);
        }
    });
}

使用指令 Angular 2 更改输入的 ngModel 值

Change an input's ngModel value using a directive Angular 2

angular2-directives

angular