autosize textarea in angular2

问题

I am working on angular2 applciation. i have a requirement to autosize textarea. I am trying to reuse the angular2-autosize from https://github.com/stevepapa/angular2-autosize

Followed the readme, But I am getting the below error

Uncaught Error: Module build failed: Error: ENOENT: no such file or directory, open 'C:\Users\Vipin\SampleApp\node_modules\angular2-autosize\angular2-autosize.js'.

Please suggest how to overcome this issue.

回答1:

Update (15.04.2018) Managed to package it, now its available as

npm install ngx-autosize

https://github.com/chrum/ngx-autosize

Old answer:

I had the same problem today and got it fixed! Please check my fork: https://github.com/chrum/angular2-autosize

Until PR is merged try:

npm install https://github.com/chrum/angular2-autosize.git --save

And then in your code, because it's slightly different, you just import module not directive...

so instead of:

import {Autosize} from 'angular2-autosize';

@NgModule({
  ...
  declarations: [
    Autosize
  ]
  ...
})

you should have:

import {AutosizeModule} from 'angular2-autosize';

@NgModule({
  ...
  imports: [
    AutosizeModule
  ]
  ...
})

回答2:

you can do like this without using the package. its simple

in controller like below

autogrow(){
  let  textArea = document.getElementById("textarea")       
  textArea.style.overflow = 'hidden';
  textArea.style.height = '0px';
  textArea.style.height = textArea.scrollHeight + 'px';
}

and in html like below

<textarea id="textarea" (keyup)="autogrow()" ></textarea>

回答3:

Slightly modified answer for tanveer's answer would be to use @ViewChild

@ViewChild('textArea', { read: ElementRef }) textArea: ElementRef;

public autoGrow() {
 const textArea = this.textArea.nativeElement;
 textArea.style.overflow = 'hidden';
 textArea.style.height = '0px';
 textArea.style.height = textArea.scrollHeight + 'px';
}

And in the HTML it would be

<textarea (keyup)="autoGrow()" #textArea></textare>

回答4:

Why you need plugins for this, it's as simple as :

<textarea (keyup)="autoGrowTextZone($event)"></textarea>

and

autoGrowTextZone(e) {
  e.target.style.height = "0px";
  e.target.style.height = (e.target.scrollHeight + 25)+"px";
}

回答5:

The requested behaviour is already implemented in angular material as documented here: Angular Material Input Autosize. This is especially useful if you are using angular material anyways.

Just use cdkTextareaAutosize as in the example:

<textarea cdkTextareaAutosize></textarea>

回答6:

Create the directive from angular-cli and add following code

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

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

constructor(public element: ElementRef) {
}
@Input() maximumHeight: number; // based on pixel
@Input() minHeight: number; // based on pixel
@HostListener('input', ['$event.target'])
@HostListener('cut', ['$event.target'])
@HostListener('paste', ['$event.target'])
@HostListener('change', ['$event.target'])

ngOnInit(): void {
    this.adjustCustom();
}

adjustCustom(): void {
    const element = this.element.nativeElement;
    element.style.height = this.minHeight + 'px';
    element.style.height = (element.scrollHeight) + 'px';
    if (element.scrollHeight <= this.maximumHeight) {

        element.style.overflowY = 'hidden'
        delete element.style.maxHeight
    } else {

        element.style.overflowY = 'scroll'
        element.style.maxHeight = this.maximumHeight + 'px';
    }

}
}

and use the directive as follows

<textarea autofocus [maximumHeight]="200" [minHeight]="43" appAutoGrow></textarea>

回答7:

I know the topic is quite old but I just change tanveer's answer to enter maximum Height as well.

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

@Directive({
  selector: '[appAutoResize]',

})
export class AutoResizeDirective implements OnInit {
  constructor(public element: ElementRef) {
  }
  @Input() maximumHeight: number; // based on pixel
  @HostListener('input', ['$event.target'])
  ngOnInit(): void {
    this.adjust();
  }

  adjust(): void {
    const ta = this.element.nativeElement;
    const maxHeghit = this.maximumHeight;
    ta.style.overflow = 'hidden';
    ta.style.height = 'auto';
    if (ta.scrollHeight <= maxHeghit) { // while current height is less than maximumHeight
      ta.style.height = ta.scrollHeight + 'px';
    } else { // greater than maximumHeight
      ta.style.height = maxHeghit + 'px';
      ta.style.overflow = 'auto';
    }
  }

}

So, you will have control on the style behavior.
I hope it can help.

回答8:

The solution that worked for me on IE as well as in the other browser

// Usage example: <textarea autoresize></textarea>

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

@Directive({
    selector: 'textarea[autosize]'
})

export class Autosize {
 @HostListener('input',['$event.target'])
  onInput(textArea: HTMLTextAreaElement): void {
    this.adjust();
  }
  constructor(public element: ElementRef){
  }
  ngAfterContentChecked(): void{
    this.adjust();
  }
  adjust(): void{
    this.element.nativeElement.style.overflow = 'hidden';
    this.element.nativeElement.style.height = 'auto';
    this.element.nativeElement.style.height = this.element.nativeElement.scrollHeight + "px";
  }
}

Add the below code to the APp.Module.ts

@NgModule({
  declarations: [
    Autosize
  ]
})

Use the tag on the HTML

 <textarea autosize></textarea>

来源：https://stackoverflow.com/questions/42827746/autosize-textarea-in-angular2

标签

angular

textarea

autosize