[英]Angular 2: summing 2 numbers with ngModel
I'm trying to sum ngModel variable with another variable and display the result as interpolation but I don't see the result updated dynamically. 我正在尝试将ngModel变量与另一个变量求和,并将结果显示为插值,但我看不到结果动态更新。
Here's my input text field: 这是我的输入文本字段:
<input type="text" [(ngModel)]='downpayment1' class="form-control" placeholder="Option 1 Down Payment (%)">
typescript code looks like this: 打字稿代码如下所示:
downpayment1 = 0;
result = this.downpayment1 + 20;
changing downpayment1 input should also change {{result}} but it doesn't happen. 更改预付定金1的输入也应更改{{result}},但不会发生。 It was much easier to evaluate a numeric expression with Angular1 but I can't find any example of this with Angular2.
用Angular1评估一个数字表达式要容易得多,但是我用Angular2找不到任何这样的例子。 What am I doing wrong here?
我在这里做错了什么?
If i understand correctly what you are trying to achieve is: 如果我正确理解您要实现的目标是:
then that would be my answer 那就是我的答案
@Component({
selector: 'my-app',
template: `
<h1>Summing example</h1>
<h2>Fixed value {{fixedValue}}</h2>
<input type="number" [(ngModel)]='downpayment1' class="form-control" placeholder="Option 1 Down Payment (%)">
<h2>Sum : {{ fixedValue + downpayment1 }}</h2>
`
})
export class AppComponent {
public fixedValue: number = 20;
public downpayment1: number = 0;
}
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