在FormGroup中使用ngModel報錯解決辦法：

一行程式碼就搞定了，在input標籤中新增即可：[ngModelOptions]="{standalone: true}"

示例：

<div class="form-group row"  [formGroup]="nameForm">
      <div class="col-sm-2"></div>
      <div class="col-sm-9">
           <input type="text" [(ngModel)]="alternative" [ngModelOptions]="{standalone: true}" class="form-control" placeholder="請輸入名稱">
      </div>
      <div class="col-sm-1"><button type="button" class="btn btn-primary btn-sm" (click)="addAlter()">提交</button></div>
</div>