Select Dropdowns in Angular 2 a built with select and option elements. You use *ngFor to loop through your values and create options and use ngModel to keep track of the value as it changes. <form #formRef="ngForm"> <select name="l…

Angular 2 forms provide RxJS streams for you to work with the data and validity as it flows out of the forms. These streams allow you handle complex scenarios and asynchronous scenarios with relative ease. This example shows you how to log out the va…

Using Radio Buttons in Angular 2 requires a basic understanding of forms as well as how their labels will match up with each input. This lesson shows how to use *ngFor with radio buttons and covers the quirks of the id property and forattributes as w…

Forms in Angular 2 are essentially wrappers around inputs that group the input values together into an object and also check that all the inputs are valid. Angular 2 ‘sngForm allows you to get a reference to that object and validity and use them to d…

In this tutorial we are going to learn how we can also implement custom form field validation in Angular 2 template driven forms, by creating our own custom validation directive. We are going to see how to write such directive and how its a best prac…

前言 之前我们学习了form表单验证用户输入格式和自动创建HTML,那么如果用户创建select标签时怎么办呢,先来看下这个东西: models.py 数据格式: class UserInfo(models.Model): caption=models.CharField(max_length=16) class UserType(models.Model): username=models.CharField(max_length=32) pwd=models.IntegerField use…

Angular 2’s ngModel exposes more than just validity, it even gives you the states of whether the input has been “touched” or changed. This lesson explains and compares those states so you can use them to make complex validity requirements. <form name…

Angular 2’s ngModel provides error objects for each of the built-in input validators. You can access these errors from a reference to the ngModel itself then build useful messaging around them to display to your users. First, you can use 'ngModel' fr…

Inputs using Angular 2’s ngModel automatically apply style classes of .ng-validand .ng-invalid each time the input’s validity changes. These classes allow you easily add your own styles simply by declaring the styles in your Componentdecorator. impor…

The ngModelGroup directive allows you to group together related inputs so that you structure the object represented by the form in a useful and predictable way. ngModelGroup is often used in combination with fieldset as they mostly represent the same…