angular 如何动态设置this.formBuilder.group Validators.required

//set validators

this.addCriteriaForm.controls["comparatorValueType"].setValidators(Validators.required);
this.addCriteriaForm.controls["comparatorValueType"].updateValueAndValidity();



this.addCriteriaForm.controls["comparatorValueType"].clearValidators();
this.addCriteriaForm.controls["comparatorValueType"].updateValueAndValidity();