调用下拉菜单的值，打字稿

如何解决调用下拉菜单的值，打字稿

我目前正在使用 Ionic Typescript。我遇到的问题是我不知道如何调用下拉列表的值（我习惯了 C# 和 java）。

该算法正在计算 IBW，只有当它超过 5 英尺时才会相加。 代码是：

{{ 1}}

import { Component } from "@angular/core";
import { NavController,Select } from "ionic-angular";


@Component({
  selector: "page-home",templateUrl: "home.html",})

export class HomePage {
  /*let R : number = 52;
  let M : number = 56.2;
  let D : number = 50;
  let H : number = 48;*/
  M: number;
  R: number;
  D: number;
  H: number;
  *inches: number;
  ft: number;
  message: string;
  sex: string = 'f' && 'm';
  constructor(public navCtrl: NavController) {}
  compute() {
    if(this.sex = 'm'){
      this.M = 56.2 + (1.41 * this.inches);
      this.R = 52 + (1.9 * this.inches);
      this.D = 50 + (2.3 * this.inches);
      this.H = 48 + (2.7 * this.inches);
    }
    else{
      this.M = 53.1 + (1.36 * this.inches);
      this.R = 49 + (1.9 * this.inches);
      this.D = 45.5 + (2.3 * this.inches);
      this.H = 45.5 + (2.2 * this.inches*);
    }
 }
}

**HOME.HTML:**

<ion-header>
  <ion-navbar>
    <ion-title>IBW Calculator</ion-title>
  </ion-navbar>
</ion-header>

<ion-content padding>
  <h2>Ideal Weight Calculator</h2>
  Height in:
  <br /><br />
  <input type="number" name="ft" [(ngModel)]="ft"> feet
  <input type="number" name="inches" [(ngModel)]="inches"> inches <br /><br />
  <select id="sex" (change)="selectChangeHandler($event)">
    <option value="m">Male</option>
    <option value="f">Female</option>
  </select>
  <br /><br />
  <button ion-button color="primary" (click)="compute()">Compute</button>
  <p>Ideal weight according to:</p>
  Miller (1983) = {{M}}kg.
  <br /> Robinson (1983) = {{R}}kg.
  <br /> Devine (1983) = {{D}}kg.
  <br /> Hamwi (1983) = {{H}}kg.
</ion-content>