Question

在尝试将[(ngModel)]放在选择标记上时，所选选项不再出现在加载页面上。在将其放置在select标签本身上之前，默认选项State刚好在我第一次加载页面时显示出来。这是我目前的代码。

HTML：

<select class="form-control" id="inputState" name="inputState" [(ngModel)]="newJob.state" required>
          <option value="" invalid selected>State</option>
          <option value="AL">Alabama</option>
          <option value="AK">Alaska</option>
          <option value="AZ">Arizona</option>
          <option value="AR">Arkansas</option>
          <option value="CA">California</option>
          <option value="CO">Colorado</option>
          <option value="CT">Connecticut</option>
          <option value="DE">Delaware</option>
          <option value="DC">District Of Columbia</option>
          <option value="FL">Florida</option>
          <option value="GA">Georgia</option>
          <option value="HI">Hawaii</option>
          <option value="ID">Idaho</option>
          <option value="IL">Illinois</option>
          <option value="IN">Indiana</option>
          <option value="IA">Iowa</option>
          <option value="KS">Kansas</option>
          <option value="KY">Kentucky</option>
          <option value="LA">Louisiana</option>
          <option value="ME">Maine</option>
          <option value="MD">Maryland</option>
          <option value="MA">Massachusetts</option>
          <option value="MI">Michigan</option>
          <option value="MN">Minnesota</option>
          <option value="MS">Mississippi</option>
          <option value="MO">Missouri</option>
          <option value="MT">Montana</option>
          <option value="NE">Nebraska</option>
          <option value="NV">Nevada</option>
          <option value="NH">New Hampshire</option>
          <option value="NJ">New Jersey</option>
          <option value="NM">New Mexico</option>
          <option value="NY">New York</option>
          <option value="NC">North Carolina</option>
          <option value="ND">North Dakota</option>
          <option value="OH">Ohio</option>
          <option value="OK">Oklahoma</option>
          <option value="OR">Oregon</option>
          <option value="PA">Pennsylvania</option>
          <option value="RI">Rhode Island</option>
          <option value="SC">South Carolina</option>
          <option value="SD">South Dakota</option>
          <option value="TN">Tennessee</option>
          <option value="TX">Texas</option>
          <option value="UT">Utah</option>
          <option value="VT">Vermont</option>
          <option value="VA">Virginia</option>
          <option value="WA">Washington</option>
          <option value="WV">West Virginia</option>
          <option value="WI">Wisconsin</option>
          <option value="WY">Wyoming</option>
        </select>

TS：

export class NewJobListingComponent implements OnInit {
  isDeleted: boolean = false;
  currentTag: string = '';
  maxTags: boolean = false;


  newJob: JobListing = {
    jobTitle: '',
    city: '',
    state: '',
    department: '',
    type: '',
    tags: []
  };
}

正如我所说，在我将[(ngModel)]放在<select ...>上之前，下拉框在页面首次呈现时正确显示了State，现在却没有。我什至尝试将newJob.state初始化为'State'，但这也不起作用。我在做什么错了？

Answer 1

通过将默认选项样式设置为display: none，尝试以下方法，它对我有用。当用户默认情况下会看到下拉列表，他们将看到State时，它将充当占位符；打开时，将不会显示State。那是hack。它就像一个占位符。

<option value="" style="display: none">State</option>

Answer 2

我改变了

  newJob: JobListing = {
    jobTitle: '',
    city: '',
    state: '',
    department: '',
    type: '',
    tags: []
  };

转到下面的代码，即可正常工作

  newJob: any = {
    jobTitle: "",
    city: "",
    state: "",
    department: "",
    type: "",
    tags: []
  };

所选属性不适用于选择标签上的[（ngModel）]

2 个答案: