== ASP.NET ==

ASP.NET is an open source cross platform web framework for C#

== [[MVC]] ==

See [[MVC]] as a concept.

The MVC model as it pertains to ASP.NET is very straightforward. There are
Models, which consist of objects, gernerally in the APPNAME.Models namespace.
Next there are Controllers, which are classes with methods for each operations
on the site (IE view/create), etc.


== Site structure ==

For some controller, XYZController, the base, or Index() of the controller, can
be accessed via mysite.com/XYZ. For other methods on the site, such as create, one must call
mysite.com/XYZ/Create. This applies for all methods in the Controller class
following signature `public IActionResult MyCustomMethod()`. These usually
end with a `return View()`. These methods are called Actions or Action Methods.

== Models ==

Models are objects in asp.net that represent entries in database tables, or
data to be processed by the backend of the application.

=== Model validation ===

Member values in a model can be validated via validation attributes. These
attributes are

* Required
* StringLength(x)
* DataType(type)
* Display(Name = "Some display name")
* Range(0,100)
* ValidateNever
* CreditCard
* EmailAddress
* Phone
* Url
* etc...

All of the validation attributes are placed in square brackets one lines above
the member values of the model. For example,

{{{
[Phone]
[Required]
public string phoneNumber { get; set; }
  }}}

All validation attributes can also be passed an argument of name `ErrorMessage`
of type string, and will be displayed on the webpage when the value is not
given.

== Controllers ==

=== Return types ===

* `View()`
  * Returns the associated view
  * Can be passed a model for data to be parsed by the view
* `RedirectToAction("Index")`
  * Redirects user to some page
  * Page is specified via the name of the Function as the Paramater

=== Action paramaters ===

Each action can take paramaters. These paramaters are URL paramaters and
their names match those sent in the URL. For example,

`public IActionResult MyAction(string name)` would take the paramater
`somesite.xyz/SomeController/MyAction?name=some_name_string`. In the controller,
the passed in arguments `name` would hold value `some_name_string` in this
instance.

== Views ==

A cshtml block may be created using a `@{}` block. Here C# can be placed,
however it is always ran by an interpretter at runtime, and is therefore not
recomended often.

=== ActionLink ===

The `@Html.ActionLink()` function can be placed inside of a `<form>` block in a
cshtml page. The arguments are as follows

{{{
@Html.ActionLink("Text Seen on page",
    "Controller",
    "Action Method",
    new { URLPARAMNAME = 1 }, null)
  }}}

Action Links are prefered, as then links do not need to be hardcoded into the
application.

=== Passing data to views ===

A view can take paramaters, primarily a single object, via passing it to the
`View()` constructor. In the .cshtml file (the view), one must then add the
line `@model APPNAME.Models.SomeModel` to specify the exact model type being
passed in.

NOTE: `@using APPNAME.Models` is required at the top of the view

=== Showing Controller data in views ===

A view can display data from a passed model via the `@Model.MEMBER_VALUE`
syntax anywhere in the HTML.

=== ViewBag ===

The ViewBag is an object that can be accessed in the Controller, and any sub
type can be apecified. IE `ViewBag.Title = "Some title"` is valid, without
declaring Title as a string or even existing first.

== Common Errors ==

=== AspNetCore.App version 6.0 not found ===

Install the runtime, `aspnet-runtime`