在Angular 6中仅允许带小数的正数 [英] Only allow positive numbers with only one decimal in Angular 6

问题描述

我是堆栈溢出的新手，所以如果我在任何地方出错，请原谅我.我对Angular 6中的问题感到困惑，我几乎没有输入类型为数字和文本的输入字段，并且我想防止用户输入除'.'以外的任何字符.(点)，并且只能输入带有单个点的正数，例如."1.22"而非"1..2."或"-1.12"或"-111".

I am new on Stack overflow so please forgive me If I am wrong anywhere. I am stuck with the problem in Angular 6, I have few input fields of type number and text and I want to prevent users from entering any character other than '.' (dot) and only enter positive numbers with a single dot for eg. "1.22" and not "1..2." or "-1.12" or "-111".

我已经尝试过(keyup)，(keypress)和(keydown)，但是它们每个对我来说都确实令人困惑.如果有任何指令或解决方案，请提出建议.在html中

I have tried (keyup), (keypress) and (keydown) but each of them works really confusing for me. Please advice if there is any directive or any solution. in html

 <input type="number"(keyup)="numberOnlyWithDecimal($event,xyz)" name="weight [(ngModel)]="xyz" min="0" step="0.1">

在.ts

public textlength=0;


numberOnlyWithDecimal(event, text): boolean {

var regex = /^\d+(\.\d+)?$/;
const charCode = (event.which) ? event.which : event.keyCode;
var text2 = text + ''
var test = text2.split(".")
if (text2) {  
  this.textlength = test.length-1 ;
}
if(text == null && charCode == 46){
  return false;
}

if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57)) {
  return false;
}
if (!regex.test(charCode)) {
  return false
}
if (charCode === 46 && this.textlength ===1 ) {
  return false
}
return true;

}

推荐答案

最后，经过大量的头脑风暴，我找到了一个可行的解决方案.我要感谢所有人的帮助，你们是救世主.

Finally, after loads of brainstorming, I have found a working solution for me. I would like to thanks all for helping me, you guys are savior.

我使用了@yanky_cranky代码并对其进行了一些修改，并且适用于数字和文本输入类型.这是代码.

I have used @yanky_cranky code and modified it a little bit and it worked for both number and text input type. Here is the code.

<input type="number" name="weight" appNumbersOnly [(ngModel)]="xyz"/>

指令:

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

@Directive({
    selector: '[appNumbersOnly]'
  })



export class NumbersOnlyDirective {
    public text;

    private regex: RegExp = new RegExp(/^-?[0-9]+(\.[0-9]*){0,1}$/g);
    private specialKeys: Array<string> = ['Backspace', 'Tab'];

    constructor(private el: ElementRef) {
    }
    @HostListener('keypress', ['$event'])
    onKeyDown(event: KeyboardEvent) {
      if (this.specialKeys.indexOf(event.key) !== -1) {
        return;
      }
      const current: string = this.el.nativeElement.value;
      const next: string = current.concat(event.key);

      if(next.includes('.')){
        if(this.text == next){
          event.preventDefault();
        }
        this.text= next;
      }
      if ((next && !String(next).match(this.regex))) {  
        event.preventDefault();
      }
    }
  }

这篇关于在Angular 6中仅允许带小数的正数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！