Angular 5：找不到模块：错误：无法解析@角/形式/src/validators

Question

我试图使用指令创建一个自定义验证器，但出现以下错误。

ERROR in ./src/app/CustomValidators/white-space-validator.directive.ts
Module not found: Error: Can't resolve '@angular/forms/src/validators' in 'D:\Angular\Admin\src\app\CustomValidators'
resolve '@angular/forms/src/validators' in 'D:\Angular\Admin\src\app\CustomValidators'
  Parsed request is a module
  using description file: D:\Angular\Admin\package.json (relative path: ./src/app/CustomValidators)
    Field 'browser' doesn't contain a valid alias configuration
  after using description file: D:\Angular\Admin\package.json (relative path: ./src/app/CustomValidators)
    resolve as module.....

指令文件中的代码：

import { Directive } from '@angular/core';
import { ValidatorFn, Validator } from '@angular/forms/src/directives/validators';
import { AbstractControl, FormControl } from '@angular/forms/src/model';
import { NG_VALIDATORS } from '@angular/forms/src/validators';

@Directive({
  selector: '[whiteSpace][ngModel]',
  providers: [
    { provide: NG_VALIDATORS, useExisting: WhiteSpaceValidatorDirective, multi: true }
  ]
})

export class WhiteSpaceValidatorDirective  {
  validator : ValidatorFn;

  constructor() { 
    this.validator = checkWhiteSpaces();
  }

  validate(c: FormControl){
    return this.validator(c);
  }
}

function checkWhiteSpaces(): ValidatorFn {
  return (c: AbstractControl) => {
    let isValid = c.value.trim().length > 0 ? true : false;
    if (isValid) {
      return null;
    }
    else {
      return {
        whiteSpace: { valid: false }
      }
    }
  }
}

我正在使用的软件包版本：

• Angular CLI:1.5.5节点：8.2.1操作系统：win32 x64 Angular:5.1.2。。。动画，通用，编译器，编译器cli，核心，窗体。。。http，
  语言服务，平台浏览器。。。平台浏览器动态，
  路由器@angular/cli:1.5.5@angular devkit/build optimizer:0.0.36@angular devkit/core:0.0.22@angular devkit/schematics:0.0.42
  @ngtools/json模式：1.1.0@ngtools/webpack:1.8.5
  @schematics/angulars:0.1.11@schematics/schematics:0.0.11
  类型脚本：2.2网页包：3.8.1

有什么帮助吗？

Answer 1

导入只是从@角/形式

import { 
      ValidatorFn,
      Validator, 
      AbstractControl, 
      FormControl, 
      NG_VALIDATORS 
} from '@angular/forms';