Quick Steps Creating Web API in ASP.NET Core 2.1 with Entity Framework

These are steps of how to quickly create Web API service in ASP.NET Core 2.1 with Entity Framework for an existing database (you will need to design in different projects and layers for a proper solution):

1. Create a new ASP.NET Core Web Application project

2. Select Web API for template

3. Install the following packages from Nuget or Package Manager console:
Microsoft.EntityFrameworkCore.SqlServer
Microsoft.EntityFrameworkCore.Tools
Microsoft.VisualStudio.Web.CodeGeneration.Design

4. On Package Manager console, run:
Scaffold-DbContext “Server=your_server_name;Database=your_db_name;Trusted_Connection=True;” Microsoft.EntityFrameworkCore.SqlServer -OutputDir Model
This will create DbContext instance and all the model classes for tables in database.

5. Open Startup.cs and comment out the whole OnConfiguring(DbContextOptionsBuilder optionsBuilder) method

6. On ConfigureServices(IServiceCollection services) method, add:

public void ConfigureServices(IServiceCollection services)
{
   services.AddMvc();
   var connection = @"Server=server_name;Database=db_name;Trusted_Connection=True;ConnectRetryCount=0";
   services.AddDbContext<MyDBContext>(options => options.UseSqlServer(connection));
}

7. Create a controller by right clicking Controller folder

8. Choose ‘API Controller with actions, using Entity Framework’

9. Select a model class which you would like to use


For allowing CORS, put these codes on Startup.cs:

services.AddCors(options => options.AddPolicy("AllowAll", p => p.AllowAnyOrigin()
                                                                      .AllowAnyMethod()
                                                                      .AllowAnyHeader()));