关于form验证

<form id=formId #refForm="ngForm">
    <div class="col-sm-9">
          <input type="text" name="caigouweight" [(ngModel)]="det['caigouweight']" class="form-control" required pattern="^([0-9]+|[0-9]{1,3}(,[0-9]{3})*)(.[0-9]{1,3})?$"/>
         <span *ngIf="refForm.controls['caigouweight']?.errors?.pattern && refForm.controls['caigouweight']?.dirty || refForm.controls['caigouweight']?.touched" class="text-danger">请填写xxx</span>
         <span *ngIf="refForm.controls['caigouweight']?.errors?.required && refForm.controls['caigouweight']?.dirty || refForm.controls['caigouweight']?.touched" class="text-danger">请填写xxx字段</span>
    </div>
    <button type="submit" [disabled]="!refForm.form.valid"></button>
</form>

<form [formGroup]="form" class="form-validate mb-lg" role="form" name="form" novalidate="">
    <div class="col-sm-9">
      <input type="text" formControlName="caigouweight" [(ngModel)]="det['caigouweight']" class="form-control"/>
      <span *ngIf="form.controls['caigouweight'].hasError('required') && (form.controls['caigouweight'].dirty || form.controls['caigouweight'].touched)"
        class="text-danger">请填写采购量</span>
      <span *ngIf="form.controls['caigouweight'].hasError('pattern') && (form.controls['caigouweight'].dirty || form.controls['caigouweight'].touched)"
        class="text-danger">请填写正确的格式</span>
    </div>
</form>

form:FormGroup;

this.form = fb.group({
  'caigouweight': [null, Validators.compose([Validators.required, Validators.pattern('^([0-9]+|[0-9]{1,3}(,[0-9]{3})*)(.[0-9]{1,3})?$')])]
})