-

1. The Mediator pattern

The Mediator pattern in .NET Core is a behavioral design pattern that reduces coupling between components by forcing them to communicate indirectly through a central "mediator" object. Instead of classes having direct references to each other, they send messages to the mediator, which then routes them to the appropriate handlers. 
Why Use It?
  • Decoupling: Objects don't need to know about each other's existence or implementation details.
  • Slim Controllers: In ASP.NET Core, it keeps API controllers thin by moving business logic into separate "handler" classes.
  • Maintainability: Centralizing communication logic makes it easier to modify or extend individual components without ripple effects.
  • CQRS Support: It is the standard way to implement Command Query Responsibility Segregation (CQRS), where "Commands" (writes) and "Queries" (reads) are handled separately

The Standard Implementation: MediatR

While you can build your own mediator, the MediatR NuGet package is the industry standard for .NET applications. 
  1. Request/Command: A simple class representing the action you want to perform (e.g., CreateUserCommand).
  2. Handler: A class implementing IRequestHandler<TRequest, TResponse> that contains the actual business logic.
  3. The Mediator: An IMediator instance (injected via Dependency Injection) that sends the request to the correct handler.

2. Repository Pattern


The Repository Pattern is a design pattern that creates an abstraction layer between an application's business logic and its data access layer. It encapsulates the logic required to access data sources, allowing the rest of the application to treat data as a simple in-memory collection.
Core Benefits
  • Separation of Concerns: Business logic remains independent of specific data access technologies like Entity Framework Core or Dapper.
  • Maintainability: Centralizing data logic prevents duplication across multiple controllers or services.
  • Testability: High-level components can be tested using mock repositories instead of a real database.
  • Flexibility: You can swap the underlying data source (e.g., from SQL Server to MongoDB) without modifying the business logic. 
Standard Implementation Steps
Implementation typically involves defining an interface and a concrete class that uses an ORM like EF Core. 
  1. Define a Repository Interface: Create an interface (e.g., IProductRepository) that defines standard CRUD operations like GetAllAsync, GetByIdAsync, and AddAsync.
  2. Implement the Concrete Repository: Create a class that implements the interface and interacts with the DbContext.
  3. Register the Repository: In Program.cs, use the built-in Dependency Injection container to register the repository as a scoped service.
  4. Inject and Use: Inject the interface into your controllers or services via the constructor. 
Common Variations
  • Generic Repository Pattern: A single generic interface (IRepository<T>) and class handle common operations for all entity types, reducing boilerplate code.
  • Unit of Work Pattern: Often used alongside repositories to group multiple repository operations into a single transaction.
  • Specification Pattern: Used with generic repositories to encapsulate complex query logic into reusable objects

Comments

Post a Comment

Popular posts from this blog

TRIGGER in sql server

-
 Trigger is a special kind of stored procedure that automatically executes when an event occurs in the database server. DML triggers execute when a user tries to modify data through a data manipulation language (DML) event. DML events are INSERT, UPDATE, or DELETE statements on a table or view. These triggers fire when any valid event is fired, regardless of whether or not any table rows are affected. For more information Types of DML Triggers AFTER trigger     AFTER triggers are executed after the action of the INSERT, UPDATE, MERGE, or DELETE statement is performed. AFTER triggers are never executed if a constraint violation occurs INSTEAD OF trigger     INSTEAD OF triggers override the standard actions of the triggering statement. Therefore, they can be used to perform error or value checking on one or more columns and the perform additional actions before insert, updating or deleting the row or rows. For example, when the value being updated in ...
Read more

What is the importance of EDMX file in Entity Framework

-
Image
ADO.NET entity is an ORM (object relational mapping) which creates a higher abstract object model over ADO.NET components. So rather than getting into dataset, datatables, command, and connection objects as shown in the below code, you work on higher level domain objects like customers, suppliers, etc. DataTable table = adoDs.Tables[ 0 ]; for ( int j = 0 ; j < table.Rows.Count; j++) { DataRow row = table.Rows[j]; // Get the values of the fields string CustomerName = ( string )row[ " Customername" ]; string CustomerCode = ( string )row[ " CustomerCode" ]; }   Benefits of using EF The main and the only benefit of EF is it auto-generates code for the Model (middle layer), Data Access Layer, and mapping code, thus reducing a lot of development time. The importance of EDMX file in Entity Framework    EDMX (Entity Data Model XML) is an XML file which contains all the mapping details of how your objects map ...
Read more

Sending Email in asp.net or mvc using gmail or other smpt.

-
Image
. how to configure email's setting to sending email by user account. I have sent a email to user when his/her registration time. In this exam. ,I have sent email address, username, password and user verify link.. I have used a snippet code of email sending. First of all, I have add the emailId,password and smpt details in web.config file.   <configSections>  <appSettings> <add key="EmailHost" value="smtp.gmail.com" />     <add key="EmailPort" value="587" />     <add key="NoReplyEmail" value="adc@gmail.com" />     <add key="NoReplyPassword" value="password" />     <add key="NoReplyEmailDisplayName" value="display name" />     <add key="Sitename" value="site name"/>     <add key="StationeryPath" value="Content\Stationery\" />   </appSettings>   <connectionStrings...
Read more