我有一个tranTypes(事务类型)数组加载到下拉列表中.在用户选择值并在返回时导航到另一个组件之后,未在下拉列表中选择该值.
从其他读物中,我了解到这是b / c对象不是同一个实例.那么在这种情况下我该怎么办？
<select name="tranType"
class="form-control"
[(ngModel)]="model.tranType"
required>
<option *ngFor="let tranType of tranTypes"
[ngValue]="tranType">{{tranType.desc}}</option>
</select>
解
ngOnInit(): void {
this.myService.getTranTypes()
.subscribe(tranTypes => {
this.tranTypes = tranTypes;
//set value of tranType if already set in the model
if (this.myService.model.tranType != undefined) {
this.myService.model.tranType = this.tranTypes.find(r => r.id == this.myService.model.tranType.id);
}
},error => this.errorMessage = <any>error);
}
从
4.0.0-beta.6开始,您可以使用自定义比较功能
原文链接：https://www.f2er.com/angularjs/143539.html<select [compareWith]="equals"
equals(o1: Country,o2: Country) {
return o1.id === o2.id;
}
对于早期版本,您可以通过比较类似于上面等于的内容来查找tranType中的tranType,然后将找到的实例分配给model.tranType以使其成为选定的实例.
