Angular2 - 输入字段只接受数字 [英] Angular2 - Input Field To Accept Only Numbers

问题描述

我有以下的HTML输入：

In Angular2, how can I mask an input field(textbox) such that it accepts only numbers and not alphabets?

在Angular2中，如何屏蔽输入字段（文本框），使其只接受数字而不是字母？ p>

I have the following HTML input:

<input type="text" *ngSwitchDefault class="form-control" (change)="onInputChange()" [(ngModel)]="config.Value" focus)="handleFocus($event)" (blur)="handleBlur($event)"/>

以上输入是一个通用文本输入，可以用作简单文本字段或作为

The above input is a generic text input which may either be used as a simple text field or as a numeric field, (for example to show the Year).

使用angular2，我该如何使用相同的输入控件并在此字段上应用某种过滤器/掩码，这样它只接受数字？
我有什么不同的方式可以实现这一点？

Using angular2, how can I use the same input control and apply some sort of filter/mask on this field, such that it accepts only numbers? What are the different ways I can achieve this?

注意：我需要仅使用文本框而不使用输入数字类型。 / strong>

Note: I need to achieve this using only textbox and not using input number type.

推荐答案

您可以使用angular2指令。 Plunkr

You can use angular2 directives. Plunkr

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

@Directive({
  selector: '[OnlyNumber]'
})
export class OnlyNumber {

  constructor(private el: ElementRef) { }

  @Input() OnlyNumber: boolean;

  @HostListener('keydown', ['$event']) onKeyDown(event) {
    let e = <KeyboardEvent> event;
    if (this.OnlyNumber) {
      if ([46, 8, 9, 27, 13, 110, 190].indexOf(e.keyCode) !== -1 ||
        // Allow: Ctrl+A
        (e.keyCode === 65 && (e.ctrlKey || e.metaKey)) ||
        // Allow: Ctrl+C
        (e.keyCode === 67 && (e.ctrlKey || e.metaKey)) ||
        // Allow: Ctrl+V
        (e.keyCode === 86 && (e.ctrlKey || e.metaKey)) ||
        // Allow: Ctrl+X
        (e.keyCode === 88 && (e.ctrlKey || e.metaKey)) ||
        // Allow: home, end, left, right
        (e.keyCode >= 35 && e.keyCode <= 39)) {
          // let it happen, don't do anything
          return;
        }
        // Ensure that it is a number and stop the keypress
        if ((e.shiftKey || (e.keyCode < 48 || e.keyCode > 57)) && (e.keyCode < 96 || e.keyCode > 105)) {
            e.preventDefault();
        }
      }
  }
}

和您需要在您的输入中将指令名称编写为属性

and you need to write the directive name in your input as an attribute

<input OnlyNumber="true" />

不要忘记在您的模块的声明数组中写入您的指令。

don't forget to write your directive in declarations array of your module.

通过使用正则表达式，您仍然需要功能键

By using regex you would still need functional keys

export class OnlyNumber {

  regexStr = '^[0-9]*$';
  constructor(private el: ElementRef) { }

  @Input() OnlyNumber: boolean;

  @HostListener('keydown', ['$event']) onKeyDown(event) {
    let e = <KeyboardEvent> event;
    if (this.OnlyNumber) {
        if ([46, 8, 9, 27, 13, 110, 190].indexOf(e.keyCode) !== -1 ||
        // Allow: Ctrl+A
        (e.keyCode == 65 && e.ctrlKey === true) ||
        // Allow: Ctrl+C
        (e.keyCode == 67 && e.ctrlKey === true) ||
        // Allow: Ctrl+V
        (e.keyCode == 86 && e.ctrlKey === true) ||
        // Allow: Ctrl+X
        (e.keyCode == 88 && e.ctrlKey === true) ||
        // Allow: home, end, left, right
        (e.keyCode >= 35 && e.keyCode <= 39)) {
          // let it happen, don't do anything
          return;
        }
      let ch = String.fromCharCode(e.keyCode);
      let regEx =  new RegExp(this.regexStr);    
      if(regEx.test(ch))
        return;
      else
         e.preventDefault();
      }
  }
}

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