提供占位符以在Angular 6中选择 [英] Give placeholder to select in Angular 6

问题描述

我有一个选择选项，我想在其中给出选择类别"的占位符

I have a select option in which i want to give placeholder which says "select a category"

<form role="form" class="form form-horizontal" (ngSubmit)="onSubmit()" #form="ngForm" ngNativeValidate>
        <div class="form-group row">
            <div class="col-xl-4 col-lg-6 col-md-12">
                <fieldset class="form-group">
                    <label for="customSelect">Categories:</label>
                    <select class="custom-select d-block w-100" id="Category" [(ngModel)]="Category" name="Category" required>
                        <option value=" ">Select one category </option>                                     
                         <option *ngFor="let item of myBusinessList" [value]="item.id">{{item.name}}</option>
                    </select>
                </fieldset>                                
            </div>
        </div>
        <button type="submit" class="btn btn-raised btn-danger">Save</button>
    </form>

如果我删除了[ngModel]，那么它将起作用.如果我写

If i remove [ngModel] then it works. If i write

<option value="undefined" selected>Select one category </option>    

然后将其视为值之一.我必须确保有地方，并且还需要选择值之一

then it considers as one of the value. I have to make sure there is place and also it is required to select one of the value

推荐答案

您可以使用 [value] =""选择隐藏的

我已经在

I have create a demo on Stackblitz

<form role="form" class="form form-horizontal" (ngSubmit)="onSubmit()" #form="ngForm" ngNativeValidate>
    <div class="form-group row">
        <div class="col-xl-4 col-lg-6 col-md-12">
            <fieldset class="form-group">
                <label for="customSelect">Categories:</label>
                <select class="custom-select d-block w-100" id="Category" [(ngModel)]="Category" name="Category" required placeholder="d.ff">
                    <option hidden [value]=""  selected>Select one category </option>
                    <option *ngFor="let item of myBusinessList" [value]="item.id">{{item.name}}</option>
                </select>
            </fieldset>
        </div>
    </div>
    <button type="submit" class="btn btn-raised btn-danger">Save</button>
</form>

这篇关于提供占位符以在Angular 6中选择的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！