如何使用 Angular 2 中的打字稿从文本框中获取值

Question

我是 angular2 / typescript 的初学者，我正在尝试从两个文本框中获取数字并将两个数字相加并使用插值显示结果

@Component({
selector: 'my-app',
template: 
`<h1>Hello {{name}}</h1>
<h1>{{D}}</h1>
 <form>
  <p>first number:<input type="text" id="num1"></p>
  <p>second number:<input type ="text1" id="num2"></p>
  <h1> {{result}}</h1>
  </form>
   <test-app></test-app>`
  })

  export class AppComponent 
  { 
 name = 'Angular'; 
 value : number;value1 : number;result:number;
  constructor(value : number,value1 : number,result:number)
  {

  this.value = parseFloat
  ((document.getElementById("text") as HTMLInputElement).value);
  this.value1 = parseFloat((document.getElementById("text1") 
  as HTMLInputElement).value);
  this.result=this.value+this.value1;
  }}

Answer 1

@Component({
  selector: 'my-app',
  template: `<h1>Hello {{name}}</h1>
  <form (ngSubmit)="onSubmit(f)">
      <p>first number:<input type="text" ngModel name="num1" id="num1"></p>
    <p>second number:<input type="text" ngModel name="num2" id="num2"></p>
</form>
<test-app></test-app>`
  })

export class AppComponent {
  name = 'Angular';

  constructor() {
  }

  onSubmit(f: NgForm) {
      console.log(f.form.value);
  }
}

Answer 2

HTML

<p>first number:<input type="number" [(ngModel)]='a'></p>
<p>second number:<input type ="number" [(ngModel)]='b'></p>
<h1>{{a + b}}</h1>

组件

export class AppComponent 
  { 
 a: number = 0; //set default value as 0
 b: number = 0;

}

Answer 3

HTML

<p>first number:<input type="text" id="num1" [(ngModel)] = "value" ></p>
<p>second number:<input type ="text1" id="num2" [(ngModel)] = "value1"></p>
<h1> {{value + value1}}</h1>

组件类

 export class AppComponent {}

Answer 4

如果你没有使用 ngModel：

var   num1= ((document.getElementById("num1") as HTMLInputElement).value);
var   num2= ((document.getElementById("num2") as HTMLInputElement).value);
var result=parseInt(num1)+parseInt(num2);
console.log(result);

Answer 5

app.component.html

<div>
      <input type='text' [(ngModel)]='userName' placeholder='user name' class='user_id_text'>
      </div>
      <div>
      <input type='password' [(ngModel)]='password' placeholder='password' class='user_id_password'>
      </div>
      <div>
      <input type='submit' value='Login' (click)='registeredUser($event)'>
      </div>

app.component.ts

export class AppComponent implements OnInit{
userName ='';
password = '';

ngOnInit(){
  console.log(this.userName+' password -'+this.password);
}
registeredUser(){
 let {userName,password} = this;

 if(userName=='ssss' && password == 'ssss'){
    console.log(userName+' password -'+password);
 }
}

} 说明 - 带有 [()] 的 ngModel 是双向绑定。 UI 中的值始终同步回您类中的域模型

Answer 6

html：

 <input type="text" id="obj_id" >

ts > 读作：

 (<HTMLInputElement>document.getElementById(obj_id)).value

如果在for循环中涉及到对象，则给出文本框 来自对象字段值的 id 然后使用 [id] 而不是 id

<input type="text" [id]="obj.field"  >

Answer 7

最简单的方法是使用模板引用变量：

@Component({
  selector: 'app-little-tour',
  template: `
    <input #newHero > 
    <button (click)="addHero(newHero.value)">Add</button>
})

export class LittleTourComponent {
  addHero(newHero: string) {
    console.log(newHero)
  }
}

可在此处找到有关 Angular 用户输入的完整指南：https://angular.io/guide/user-input