Default invalid select option in Angular 2 model-driven forms?

Question

Is there any way to achieve an invalid default select option in an Angular 2 model driven form?

I'm looking for something like this:

<select name="DateExpiryMonth" [(ngModel)]="model.DateExpiryMonth" ngControl="dateExpiryMonth" required>
    <option value="" selected="selected" disabled>Month...</option>
    <option *ngFor="let month of months" [value]="month">{{ month }}</option>
</select>

Ideally, the required attribute on the select would ensure that the first <option> would be considered invalid by Angular 2, yet I can't find any documentation that suggests this is possible.

As it stands, the first "Month..." option is considered valid by Angular 2.

Answer 1

我不认为这是一个理想的解决方案，但我发现如果我将模型中的字段设置为null或undefined（在您的情况下为model.dateExpiryMonth ），则angular会认为表单无效。