Angular 2 - 异常 : _this. 订阅不是函数 - 自定义验证

Question

我正在尝试实现自定义验证规则来验证复选框是否被选中。

但是我遇到了一个错误

error_handler.js:46 EXCEPTION: _this.subscribe is not a function

当我尝试添加自定义验证器时

validator.ts

 import {Control} from "angular/common";

 interface ValidationResult {
     [key: string]: any;
 }

 export class CustomValidators {

     static validateChecked(c: Control): ValidationResult {
         return (c.value);
     }
 }

Component.ts

import {Component} from '@angular/core';

import {FormBuilder, FormGroup, Validators, FormControl} from '@angular/forms';
import {CustomValidators} from './validators.ts'

@Component({
    selector: 'wizard',
    templateUrl: './template.html',
})

/**
 * @todo - check how first select is automatically active
 * @todo - export form presets to form class
 */
export class Wizard {
    myForm: FormGroup;

    privacy: boolean;


    // Prefilling the FormBuilder
    constructor(private horizonService: HorizonService, fb: FormBuilder) {
        this.myForm = fb.group({
            'privacy': ['', Validators.required, CustomValidators.validateChecked],
        });
    }

    onSubmit(values: string): void {
        console.log('you submitted value: ', values);
    }
}

Answer 1

如果您需要多个验证器，您应该使用 Validators.compose。所以你的代码应该是这样的:

constructor(private horizonService: HorizonService, fb: FormBuilder) {
    this.myForm = fb.group({
      'privacy': ['', Validators.compose([Validators.required, CustomValidators.validateChecked])],
    });
  }

您可以阅读一篇关于验证器的精彩文章 here .