Angular2 - 使用NgFor时,每个键盘后双向绑定文本输入模糊

Question

所以在Angular2应用程序中我有一个名为'recipe.ingredients'的字符串数组,我有一个表单设置允许您编辑成分,添加和删除文本字段(和数组中的项目)的按钮.

    <ul class="list-unstyled">
      <div class="row" *ngFor="let ingredient of recipe.ingredients; let i=index">
        <li>
          <div class="col-xs-4">
            <input
              size="20"
              type="text"
              class="form-control"
              [ngModel]="recipe.ingredients[i]"
              #t
              (blur)="recipe.ingredients[i]=t.value"
              required>
          </div>
          <div class="btn-group col-xs-2" role="group">
            <button
              type="button"
              class="btn btn-default btn-xs"
              (click)="recipe.ingredients.splice(i,1)">-</button>
            <button
              type="button"
              class="btn btn-default btn-xs"
              (click)="recipe.ingredients.splice(i+1,0,'')">+</button>
          </div>
        </li>
      </div>
    </ul>

你会注意到我没有用[(ngModel)]双向绑定到recipe.ingredients [i],那是因为我试过了,每次你输入一个字符时,文本框都会失去焦点.我认为这与*ngFor踩过数组有关.无论如何,目前这种解决方法很好,但现在我添加了一些功能,我需要两种数据绑定才能工作.知道如何重构这个以使其工作吗？

Answer 1

用途trackBy:

<div class="row" *ngFor="let ingredient of recipe.ingredients; let i=index; 
 trackBy:customTrackBy">

  [(ngModel)]="recipe.ingredients[i]"

customTrackBy(index: number, obj: any): any {
  return index;
}

感谢冈特:/sf/answers/2552924881/,可与本作中找到SO搜索:https://stackoverflow.com/search?q=%5Bangular2%5D+ngfor+ngmodel

另一种解决问题的方法如/sf/answers/2335619471/所示,是使用对象数组而不是基元数组.而不是

recipe = { ingredients: ['salt', 'flour'] };

使用

recipe = { ingredients: [{item: 'salt'}, {item: 'flour'}] };