在 Angular2 的自定义验证器中注入服务

我尝试使用自定义验证器中的服务来检查用户名是否已存在。

import {Component} from 'angular2/core';
import {
    Control,
    ControlGroup,
    FormBuilder
} from "angular2/common";
import {CharacterService} from "./character-service";

@Component({
    selector: 'register-character-form',
    template: `
        <h2 class="ui header">A new adventurer is coming...</h2>
        <form (ngSubmit)="register()" [ngFormModel]="characterForm" class="ui form">
            <div class="field">
                <label>Nom</label>
                <input ngControl="name">
            </div>
            <button type="submit" class="ui button">Enter in the adventure</button>
        </form>
    `,
    providers: [CharacterService]
})
export class RegisterCharacterFormCmp {
    characterForm: ControlGroup;
    name: Control;

    constructor(private _characterService: CharacterService, fb: FormBuilder) {
        this.name = fb.control('', this.characterNameValidator);

        this.characterForm = fb.group({
            name: this.name
        });
    }

    register(): void {
        //TODO: To implement
    }

    // Not works, this binds the control
    characterNameValidator(control: Control) {
        return this._characterService.isCharacterNameAlreadyExists(control.value) ? {nameCharacterAlreadyExistsError: true} : null;
    }
}

这不起作用。在characterNameValidator中，“this”引用的是控件而不是我的类。该服务未定义。如何在验证器中使用我的服务？

在全球范围内，如何在自定义验证器中传递参数？

你需要控制什么this意味着你的验证。你可以这样做bind https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

this.name = fb.control('', this.characterNameValidator.bind(this));

那么其他一切都应该按预期工作。