this.form.controls["firstName"].setValidators([Validators.minLength(1), Validators.maxLength(30)]); Note, this will reset any existing validators you added when you created the FormControl. …

2017年5月8日 · However, this will not work for Validators.minLength(), Validators.maxLength(), Validators.min(), Validators.max or any validator that needs a parameter. To make it work, you …

2017年8月7日 · You have two ways to add validators to a form control. Using imperative approach by specifying them as a parameter to a form control: const ctrl = new FormControl('', …

2012年11月2日 · With a little bit of reflection, you could auto-find all validators that a composite validator should wire up to (i.e. find all the interfaces and base class chains and see if there's …

2016年3月21日 · I made a custom validator, but the conditional variables that I pass to the custom validator are static and remain their initial values. What should my custom validator look like to …

2016年10月4日 · According to thoughtgram.io, the currently supported validators are: required minlength maxlength pattern So, considering the following code (plunkr here): @Component({ …

2016年8月30日 · Learn how to validate white spaces and empty spaces in Angular 2 forms.

2016年6月28日 · Validators.minLength and Validators.maxLength won't work for below as the input type is number/non-string hence the length cannot be really checked here. <input …

2018年1月20日 · You're mixing validators that validate a whole group (MatchPassword, PasswordRequirements), and which thus need to be set on the group, with a validator that …

2012年10月9日 · Why has ASP.NET added this JavaScript code, that is run on form submission? var Page_Validators = new Array(document.getElementById("rfvOthers"));