Overview

Razor Class Libraries can contain Razor views, pages, controllers, page models, Razor Components, View components, and data models along with their associated static files. They can be packaged and reused.

Creating

Visual Studio project type = Razor Class Library dotnet new razorclasslib

ASP.NET Core templates assume RCL content is in Areas folder.

Precedence

When a view, partial view, or Razor Page exists in both the web app and the RCL, the web app takes precedence over (overrides) the one in the RCL.

RCL Pages layout

To reference RCL content as though it is a part of the web app’s Pages folder, create the RCL project with this structure:

RazorUIClassLib/Pages
RazorUIClassLib/Pages/Shared

Create an RCL with Static Assets

Create a wwwroot folder in the class library and include any required files in that folder. The dotnet pack command automatically includes this folder in the package.

Exclude Static Assets

Add this to csproj:

<PropertyGroup>
  <DefaultItemExcludes>$(DefaultItemExcludes);wwwroot\lib.css</DefaultItemExcludes>
</PropertyGroup>

Using an RCL in a Component

1. Add a project reference from the Component’s project to the RCL project
2. Add a @using directive either in the Component directly or in _Imports
3. (if RCL uses static assets) Bring in the CSS on the hosting page (index.html or host.cshtml)
   Note the _content prefix that is required when referencing a project other than the current one:

<link href="_content/BethanysPieShopHRM.ComponentsLibrary/leaflet/leaflet.css" rel="stylesheet" />

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