ionic2向Backand发送对象数据

Question

我创建了一个ionic2注册页面。在注册页面上，我创建了一个下拉菜单，用户可以在其中选择自己的血型。我正在试着把选定的血型发送到Backand数据库。我不确定我做错了什么，因为选定的血型在Backand中没有显示。

signup.ts

import {Component} from '@angular/core';
import { BackandService } from '@backand/angular2-sdk'
import { LoginPage } from '../login/login';
import { AlertController } from 'ionic-angular';

@Component({
   templateUrl: 'signup.html',
   selector: 'page-signup',
})

 export class SignupPage {

  email:string = '';
  firstName:string = '';
  lastName:string = '';
  signUpPassword: string = '';
  confirmPassword: string = '';
  bloodType: Object = {};


  constructor(private backand: BackandService, private alertCtrl: 
  AlertController) {}


  public signUp() {

   this.backand.signup(this.firstName, this.lastName, this.email,this.signUpPassword, this.confirmPassword, this.bloodType)
  .then((res: any) =>
   {
    let alert = this.alertCtrl.create({
    subTitle: 'Thank you for signing up.',
    buttons:['Login']
    });
    alert.present();
    this.email = this.signUpPassword = this.confirmPassword = this.firstName= this.lastName = this.bloodType = '';
    }
   );
  }
}

signup.html

<ion-item>
    <ion-label>Select Your Blood Type</ion-label>
    <ion-select type="text" (input)="bloodType = $event.target.value" ng-model="bloodType">
      <ion-option>O Positive</ion-option>
      <ion-option> O Negative</ion-option>
      <ion-option> A Positive</ion-option>
      <ion-option> A Negative</ion-option>
      <ion-option> B Positive</ion-option>
      <ion-option> B Negative</ion-option>
      <ion-option> AB Positive</ion-option>
      <ion-option> AB Negative</ion-option>
      <ion-option> Unknown</ion-option>
    </ion-select>
 <ion-item>

Answer 1

我自己想出来的。在signup.ts中应该是，

 this.backand.signup(this.firstName, this.lastName, this.email,this.signUpPassword, this.confirmPassword, {"bloodType": this.bloodType})

在signup.html中应该是

<ion-select type="text" (input)="bloodType = $event.target.value" [(ng-model)]="bloodType">