Angular 2

Template-Driven

• Template-Driven Forms use a combination of builtin Directives and local template variables to handle the form:
  • NgForm - Allows getting form information and override default submit behavior
  • NgControl - ​Directive for tracking state and naming of each form elements in ngForm.
  • NgSumbit - Exectues an event handler on button type="submit"
• By default the <form> element is selected by NgForm Directive even if not explicitly specified. This can be reverted using the NgNoFrom Directive on <form> element.

Template-Driven

• Local template variables are used on the form and each input to get information
  • Local variables in this context get the content of the Directives ngForm, ngControl and not the element.
    This is why the syntext is
    #<variable>="ngForm" (ngForm is exported from these directives)
• Local variables can be used to check validations either at input level or Form level
• Local variables can be used to send specific or all Form data in the ngSubmit event handler

Template-Driven

• Builtin validation are supported:
  • required - Requires a form control to have a non-empty value
  • minlength - Requires a form control to have a value of a minimum length
  • maxlength - Requires a form control to have a value of a maximum length
  • pattern - Requires a form control’s value to match a given regex
• Custom validation can be added using Directive that uses validator API

Template-Driven

• Example

<form #f="ngForm" (ngSubmit)="onFormSubmit(f.value)">
    <label>Name:</label><input type="text" ngControl="name" #name="ngForm" required /><br />
    <div [hidden]="name.valid" [style.color]="'red'">Invalid name input</div>
    <label>Email:</label><input type="text" ngControl="email" #email="ngForm" /><br />
    <div [hidden]="email.valid " [style.color]="'red'">Invalid email input</div>

    <button type="submit" [disabled]="!f.valid">Submit</button>
</form>