当组件为空时，如何隐藏表元素？

Question

html正在打印表中的所有API数据。产品和组件当组件为空时，表格不应打印产品。最好的方法是什么？我用的是角度8

产品={"id"： 1，"name"："John"，"组件": [ { "id"： 130，"name"："Price", } ] "isSelected"： false}

产品={“id”：2，“name”：“name”，“components”：[]}

 <div class="card">
        <div class="card-body">
                <table class="table table-striped table-bordered hover">
                    <thead>
                        <tr>
                            <th width="1%" class="text-center"></th>
                            <th width="8%" class="text-center">Id</th>
                            <th width="8%" class="text-center">Name</th>
                        </tr>
                    </thead>
                    <tbody>
                        <ng-container *ngFor="let product of products; index as i">
                            <tr>
                                <td>
                                    <div>
                                        <button class="btn btn-sm btn-default"></button>
                                    </div>
                                </td>
                                <td>{{product.id}}</td>
                                <td>{{product.name}}</td>
                            </tr>
                            <tr *ngFor="let prodComp of product.components">
                                <td></td>
                                <td>{{prodComp.id}}</td>
                                <td>{{prodComp.name}}</td>
                            </tr>
                        </ng-container>
                    </tbody>
                </table>
        </div>
    </div>

Answer 1

您可以使用ngIf在您的ngFor中添加另一个容器来测试该条件：

                <ng-container *ngFor="let product of products; index as i">
                    <ng-container *ngIf="product.components.length > 0">
                        <tr>
                            <td>
                                <div>
                                    <button class="btn btn-sm btn-default"></button>
                                </div>
                            </td>
                            <td>{{product.id}}</td>
                            <td>{{product.name}}</td>
                        </tr>
                        <tr *ngFor="let prodComp of product.components">
                            <td></td>
                            <td>{{prodComp.id}}</td>
                            <td>{{prodComp.name}}</td>
                        </tr>
                    </ng-container>
                </ng-container>