Angular 4中用于Json对象数组的自定义管道过滤器

Question

I have an array, that consists a list of json objects as items. I am using this array as an options list for two select controls, here I want to hide first select control selected items in second select control options list.

Is it possible to do?

Answer 1

I don't know why are you looking for a pipe/filter solution when it can be done so easily without pipe? I may not be knowing entire scenario of yours but what you have written according to that a simple solution would be,

<select class="form-control" [(ngModel)]="selectedCity">
     <option *ngFor="let ct of cities" [value]="ct.id">{{ct.name}}  
</select>



// look at [disabled]="selectedCity==ct.id"

 <select class="form-control" [(ngModel)]="selectedOtherCity">
     <option [disabled]="selectedCity==ct.id" *ngFor="let ct of cities" [value]="ct.id">{{ct.name}}  
</select>

detailed code could be found here : https://plnkr.co/edit/gkvFqtyddLVEsFOE07Ls?p=preview