Angular 2使用ngFor设置和绑定复选框

Question

我有这样一个数组:

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

这样的模板:

<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,如果选中1复选框,则设置为true.我该如何单独设置？

Answer 1

我在使用最新版本的Angular 2来解决此问题时遇到了一些麻烦。这就是我想对对象列表进行双向绑定的方法，该对象列表包含角色名称和检查角色时的布尔值。

<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只是一个简单的类，具有两个字段：

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

并且在组件中，我必须在创建FormGroup时声明一个名为role的属性，然后将其绑定到上面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，在提交表单后，ngSubmit方法只需要提取所需的内容：

 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
    }
 }

Answer 2

我想这就是你想要的:

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

更新 使用(ngModelChange)通常比好(change),特别是如果[ngModel]使用

<input type="checkbox"  
    (ngModelChange)="expression && expression[obj.name]= $event ? true : undefined"
    [ngModel]="expression && expression[obj.name]">