typescript - Angular 2 使用 ngFor 设置和绑定(bind)复选框

Question

我有一个这样的数组:

 objectArray = [
        {"name": "Car"},
        {"name": "Bike"},
        {"name": "Boat"},
        {"name": "Plane"}
    ];

模板是这样的:

<li *ngFor="#obj of objectArray">
   <a href="#" class="small" data-value="option1" tabIndex="-1">
      <input type="checkbox" (change)="expression && expression.value = $event.target.checked ? true : undefind" [ngModel]="expression?.value">
      <label for="">{{ obj.name }}</label>
   </a>
</li>

但是当 1 个复选框被选中时，这将被设置为真。我该如何单独设置它？

Answer 1

我在使用最新版本的 Angular 2 解决这个问题时遇到了一些麻烦。这是我想出的方法，可以双向绑定(bind)到包含 Angular 色名称和 bool 值的对象列表，用于检查 Angular 色。

<form [formGroup]="userInfoForm" (ngSubmit)="onSubmit(userInfoForm)">

...

 <input type="hidden" name="roles" formControlName="roles" [(ngModel)]="roleSelections">
 <div *ngFor="let role of roleSelections">
     <input type="checkbox" 
            [value]="role.isChecked" 
            [checked]="role.isChecked" 
            (change)="$event.target.checked ? role.isChecked = true : role.isChecked = false">
       {{role.name}}
 </div>

RoleSelection 只是一个具有两个字段的简单类:

export class RoleSelection {
constructor(
    public name: string,
    public isChecked: boolean)
    { }
}

在组件中，我必须在创建 FormGroup 时声明一个名为 roles 的属性，然后将其绑定(bind)到上面 HTML 中的隐藏字段。

    this.userInfoForm = new FormGroup({
        emailAddress: new FormControl(this.userInfo.emailAddress, Validators.required),
        firstName: new FormControl(this.userInfo.firstName, Validators.required),
        middleName: new FormControl(this.userInfo.middleName),
        lastName: new FormControl(this.userInfo.lastName, Validators.required),
        isAdmin: new FormControl(this.userInfo.isAdmin),
        isArchived: new FormControl(this.userInfo.isArchived),
        roles: new FormControl(this.roleSelections)
    });

然后在提交表单时，ngSubmit 方法只需要提取它需要的内容:

 private onSubmit(obj: any) {
    if (obj.valid) {
        let account: IUserAccount = {};
        account.id = this.userAccountId;
        account.firstName = obj.controls.firstName.value;
        ...
        ...
        // get list of roles checked via obj.controls.roles.value[i].isChecked etc
        ...
        ...
        // do submission
    }
 }