arrays - 在 ngFor 中合并两个数组

Question

我有两个数组-a，我从服务中得到:

handleProjectLoaded(project){

    this.projectService.getCodesByType( "Structure" ).subscribe( response => {

        this.structures = response;
    });

    this.projectService.getCodesByType( "Direction" ).subscribe( response => {

        this.lines = response;
    });
}

一个数组在结构中，第二个我在行中。我将它们分开放在 html 中，并显示了 ngFor。

<div class="div-width-button3">
    <select #lineSelect class="custom-select custom-select-project" style="flex-basis:49%" (change)="addDirection(directionSelect.value); directionSelect.selectedIndex = 0;">
        <option selected disabled value="">Add a direction</option>
        <option *ngFor="let direction of directions" [value]=direction.id
            [selected]="direction.id==directionSelect.value">{{direction.name}}</option>
    </select> 
    <select #structureSelect class="custom-select custom-select-project"  style="flex-basis:49%"
        (change)="addStructure(structureSelect.value); structureSelect.selectedIndex = 0;">
        <option selected disabled value="">Add a structure</option>
        <option *ngFor="let structure of structures" [value]=structure.id
            [selected]="structure.id==structureSelect.value">{{structure.name}}</option>
    </select>
</div>

我需要一个解决方案来将这两个数组显示为一个 ngFor。有什么办法可以合并它们吗？？

Answer 1

我没有测试过，但是为什么不用concat呢？

<option *ngFor="let line of lines.concat(structures)" [value]="line.id">{{ line.name }}</option>