在Angular 6中动态选择选项

Question

如何在Angular 6中动态选择option？该页面上有许多select，如下所示：

如果选项的值等于parcela.forma_parcela，如何动态选择？

parcela.forma_parcela = [0,1,2,3,4,5,6];

<select (change)="setBancoParcela($event.target.value, parcela)" class="input-default" name="forma_pagamento_1" id="forma_pagamento_1">
    <option value="0" [selected]="parcela.forma_parcela == this.value">Banco</option>
    <option value="1" [selected]="parcela.forma_parcela == this.value">BNDES</option>
    <option value="2" [selected]="parcela.forma_parcela == this.value">Boleto</option>
    <option value="3" [selected]="parcela.forma_parcela == this.value">Cartão de Crédito</option>
    <option value="4" [selected]="parcela.forma_parcela == this.value">Cartão de Débito</option>
    <option value="5" [selected]="parcela.forma_parcela == this.value">CH Descontado</option>
    <option value="6" [selected]="parcela.forma_parcela == this.value">Cheque</option>
    <option value="7" [selected]="parcela.forma_parcela == this.value">DDA</option>
    <option value="8" [selected]="parcela.forma_parcela == this.value">Débito Automático</option>
    <option value="9" [selected]="parcela.forma_parcela == this.value">Depósito em C/C</option>
</select>

Answer 1

使动态变化的正确方法是：

<select id="select-type-basic" [(ngModel)]="status">
    <option *ngFor="let status_item of status_values">
    {{status_item}}
    </option>
</select>

值应避免在选项内部使用，因为这将设置“选择字段”的默认值。默认选择应该与[（ngModel）]绑定，并且应该同样声明选项。

status : any = "Completed";
status_values: any = ["In Progress", "Completed", "Closed"];

Answer 2

您可以使用ngModel指令，并从类中导出选项。

Answer 3

我用<option *ngFor="let forma of formas_pagamentos" value="{{forma.value}}" [selected]="forma.value == parcela.forma_parcela">{{forma.nome}}</option>

解决了这个问题

Answer 4

尝试

 <select
       class="custom-select"
       name="ratings"
       [ngModel]="ratings.OverallRating">
       <option 
        *ngFor="let orc of ratings?.RatingChoices"
         [value]="orc.ratingChoice">
         {{orc.ratingDescription}}
       </option>
    </select>