How to Validate FormArray length in angular2
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效,请关闭广告屏蔽插件后再试): 问题: I have a data driven form in angular2 like below this.formBuilder.group({ 'name': ['',Validators.required], 'description': ['', Validators.required], 'places': this.formBuilder.array([], Validators.minlength(1)) }) I want to add validations to the place formArray, so i am adding minlength validation, but minlength validation is not working on formArray. What are the other validations for formArray, so that form must be valid only when places array contain atleast one place. 回答1: Add this custom validator to your validation service: