Angular 2 (Angular 4) – Form Validation Messages

In this video we take a look at implementing angular 2 validation message in our app component code instead of directly in our HTML as we used to do in AngularJS.

Point being we may wish to test our validation logic at a later date, as well as keep our HTML clean, which is something AngularJS caused issues with over time. We also take the bootstrap css for validation errors and apply them to the ng-invalid class in our component stylesheet.

We also look at the ngAfterViewChecked lifecycle event to be able to subscribe into being able to monitor changes to the input controls, so we can update validation messages based on any changes to our input controls on the form.

To follow along with this tutorial please clone down the following branch, then checkout the tutorial12 branch. If you wish to see the final result, check out the tutorial13 branch.

https://github.com/lyraddigital/angular2tutorial.git

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Watch all my other videos in this series:-

Part 1 – Introduction and the CLI: https://www.youtube.com/watch?v=QzXdiH3wJp0
Part 2 – Angular Module Basics: https://www.youtube.com/watch?v=GeomqoUUCho
Part 3 – Multiple Angular Modules: https://www.youtube.com/watch?v=33ADKstmXqQ
Part 4 – Shared Angular Modules: https://www.youtube.com/watch?v=QExtdZKqw1E
Part 5 – Eagerly and Lazily Loading Modules: https://www.youtube.com/watch?v=0YC4qmnkMbU
Part 6 – Basic App Component and Presentation: https://www.youtube.com/watch?v=np7rZUob-CY
Part 7 – App Component bindings: https://www.youtube.com/watch?v=RmC8B_GaONM
Part 8 – Attribute binding and the main navigation: https://www.youtube.com/watch?v=OxjR7lFP430
Part 9 – Basic Form and Dual Binding: https://www.youtube.com/watch?v=23HsTwj7oAw
Part 10 – Registration Form Part 1: https://www.youtube.com/watch?v=ysEYpkQ-wbU
Part 11 – Registration Form Part 2: https://www.youtube.com/watch?v=xUaz3GULoIQ
Part 12 – Registration Form Part 3: https://www.youtube.com/watch?v=8iPb-4dNpWo
Part 14- Registration Form Part 5: https://www.youtube.com/watch?v=q7mkQmqL0JM
Part 15 – Structural Directives: https://www.youtube.com/watch?v=Iw1H15Aeg5s
Part 16 – Dynamic Forms: https://www.youtube.com/watch?v=nxa78ZxeNdI

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