Gain insights into creating dynamic web apps with ASP.NET Core MVC. Explore Razor, localization, advanced features, and best practices for building public and business applications.

ASP.NET Core MVC (Intermediate)_468 x 60 copy.png

asp.tar.gz

ASP.NET

ASP.NET-multi

ASP.NET-Secure

ASP.NET-copy

In this course, you will learn how to create a modular, dynamic web application with ASP.NET Core MVC, Razor, and Razor tag-helpers. Furthermore, you will also learn how to localize that application in several languages, and finally how to publish it.

You will cover many different aspects of ASP.NET development including: how to optimize user interfaces, validate user input, how to write clean and maintainable code with dependency injection and configuration data, and a whole lot more.

By the end of this course, you will be able to build both a public website and a business application based on ASP.NET Core MVC, with advanced features such as caching, authentication, and authorizations, and while conforming to Microsoft best-practices.

ASP.NET Core MVC

A tag helper is a class that inherits from the framework `Microsoft.AspNetCore.Razor.TagHelpers.TagHelper` abstract class:

using Microsoft.AspNetCore.Razor.TagHelpers;
...
namespace MvcProject.TagHelpers
{
    public class ProtocolTagHelper: TagHelper
    {
      ...
    }
}

# Defining when the tag helper is applied ##

The first step in tag helper design is to code its hook conditions, that is, to define when the transformation encoded in the tag helper applies. This can be done with one or more `HtmlTargetElement` attributes applied to the tag helper class definition. Each attribute specifies an alternative condition. This means that it is enough that the condition specified by a single attribute is satisfied for the tag helper transformation to apply.

Each `HtmlTargetElement` attribute can specify one or more of the following

* The name of the tag that the tag helper applies to.
```C#
[HtmlTargetElement("protocol")]
public class ProtocolTagHelper: TagHelper
```
* Some names of attributes that the tag must contain. In this case, the name of the tag is optional-
```C#
[HtmlTargetElement(Attributes = "attr1,attr2")]
public class ProtocolTagHelper: TagHelper
``` 
* The name of the parent tag. In this case, the name of the tag is optional.
```C#
[HtmlTargetElement(ParentTag= "div")]
public class ProtocolTagHelper: TagHelper
``` 
All conditions stated in an `HtmlTargetElement` attribute must be verified simultaneously for the tag helper to be executed. Alternative conditions can be coded by adding other `HtmlTargetElement` attributes. For instance, if we want to implement a tag helper that renders a `strong` element when either the tag name is `bold`, or any other element contains a `bold="true"` attribute, we may write:

```C#
[HtmlTargetElement("bold")]
[HtmlTargetElement(Attributes = "bold")]
public class BoldTagHelper: TagHelper
``` 
Another property that defines when a tag helper is applied is its priority. Priority determines the order of execution when several tag helpers apply to the same tag. It is defined by overriding the `Order` read-only property inherited from the `TagHelper` class as shown below:

In this lesson, we will learn how to code our custom tag helpers.

Razor Template Language

Razor Language Assessment

Tag Helpers

Tag Helpers Assessment

Controllers and ViewModels

Controllers Assessment

Validation and Metadata

Validation Assessment

Dependency Injection

Configuration and Options Framework

Localization and Globalization

Factoring out UI Logic

Authentication and Authorization

Advanced Topics Assessment

Publishing Your Web Application

Conclusion

Appendix

Authoring Tag Helpers

Defining when the tag helper is applied