\libraries\nop.core
The Nop.core project contains a series of core classes of nopcommerce such as caches, events, auxiliary classes, and business objects (such as orders and customer entity classes)
\libraries\nop.data
The Nop.data project contains a series of data access classes and methods to read and save data from a database or other data medium. It also helps to separate data access logic from your business objects. Nopcommerce uses the entity Framework (EF) Code-first method, which allows you to define entities in Nopcommerce code (all core entity classes are defined in Nop.core), and then let EF generate the database. That's why it's called Code-first. You can then query the object using LINQ, which itself transforms the query into an SQL statement and executes it in the database. Nopcommerce has a Cow B API that lets you fully customize the persistent mapping, and you can find code-first information here and here.
\libraries\nop.services
This project contains a series of core services, business logic, validation, and, if there is data, a method of computing data, the legendary Business Access Layer (BAL)
Those items in the \plugins\ folder
Plugins is the solution folder for VS, it is in the root directory of your solution on the hard drive. Because the entry path for the project at compile time is ". \.. \presentation\nop.web\plugins\{group}. {name}\, so the DLL for the plugin is automatically placed in the \presentation\nop.web\plugins\ folder to place the deployed plug-in. This also allows the plugin to include static files such as CSS or JS, without having to copy the files between projects.
\presentation\nop.admin
Nop.admin is an MVC project and if you've never used ASP. NET MVC, please hit here for more information. You may have guessed that this is the management background in the presentation layer, and you can find it in the \presentation\nop.web\administration folder and the project cannot run.
\presentation\nop.web
Nop.web is also an MVC project, the presentation layer of the front-desk shop, this is the project you really want to run up, it is also the beginning of the entire application project.
\presentation\nop.web.framework
Nop.Web.Framework is a class library project that represents a layer, including some common presentation features that can be used in the background and foreground.
\test\nop.core.tests
Nop.Core.Tests is Nop.core's test project.
\test\nop.data.tests
Nop.Data.Tests is Nop.data's test project.
\test\nop.services.tests
Nop.Services.Tests is Nop.services's test project.
\test\nop.tests
Nop.tests is a class library that contains a common class and helper method to be used in other test projects, and this project does not contain any test cases
Nopcommerce Solution Catalog Explained