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The error message arises if you want to extend an application with EF Entity Framework on Core 2 MVC.

As soon as you start the migration, the Feher comes:

No DbContext was found in assembly


Error message in the Package Manager Console

PM> add-migration 01Start


      User profile is available. Using 'C:\Users\Raimund\AppData\Local\ASP.NET\DataProtection-Keys' as key repository and Windows DPAPI to encrypt keys at rest.

No DbContext was found in assembly 'ArtikelWeb'. Ensure that you're using the correct assembly and that the type is neither abstract nor generic.




You have to create a DbContext class under Models that represents the tables to the outer SQL Server database.

In Entity Framework, the database is called dbContext and dbSet is the tables.

The text myWebApp_ must be adapted to the name of your own application

    public class DbContext_Model



        public class MyWebApp_Context : DbContext


            public myWebApp_Context(DbContextOptions< myWebApp_Context> options)

                : base(options)

            { }


            public DbSet<Products > Products { get; set; }           




For this you have to insert the line EntityFrameworkCore at Asp.Net Core

using Microsoft.EntityFrameworkCore;


In the directory / Models



Then add the database connection to the Startup.cs file



Entry of the connection in the section ConfigureServices.

The name myWebApp must be adapted to the name of your own application

public void ConfigureServices(IServiceCollection services)



            var connection = @"Server=(localdb)\mssqllocaldb;Database=myWebApp;Trusted_Connection=True;";

            services.AddDbContext<myWebApp_Context>(options => options.UseSqlServer(connection));



And in the Import section of Startup.cs, you need to add a reference to the .Models directory and a reference to DbContrext file

using test_EF_Core2.Models;

using Microsoft.EntityFrameworkCore;

using static test_EF_Core2.Models.DbContext_Model;


Before you can migrate the application with EF Entity Framework, you still have to set a Primary Key in the Model classes / Tables.

Here you put the attibut line [Key] in front of the field entry, which represents the ID column.

using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations;

using System.Linq;

using System.Threading.Tasks;


namespace test_EF_Core2.Models


    public class Products



        public int IDProduct { get; set; }

        public string Title { get; set; }





Migration and transfer from SQL Server

# Code First

First step ... create the migration

PM> Add-Migration InitialCreate


This creates a directory / migration and adds the current migration file to Date_Name.cs


And then you transfer the structure to SQL Server:

PM> Update-Database



Database in SQL Server


The SQL Server Object Explorer is preinstalled in Visual Studio and is located in Menu-> View-> SQL Server Object Explorer.

If you then on SQL Server -> (localdb) -> Databases lists the databases, then you will find the same name database in the directory.


It is important that in each case a primary key has been adopted in the tables.


The statement PM> Update Database thus creates the correct SQL Server Transscript files on the SQL Server.

With the matching T-SQL script.

CREATE TABLE [dbo].[Products] (

    [IDProduct] INT            IDENTITY (1, 1) NOT NULL,

    [Title]     NVARCHAR (MAX) NULL,






This is so important that when entering new data sets, the ID is incremented uniquely and thus a fast and clear structure is available.


Video tutorial on the solution

[Lnk "" /]


Installation of .NET Core 2.1 on a web server
Set upload of very large files in Asp.Net MVC Core 2.
Error: Identity column can not be updated, IDENTITY_INSERT is set to OFF
Asp Error: IDENTITY_INSERT OFF when accessing AspNetUsers registry
ASP IIS Error: 440.13 Not Found. upload file size is exceeded
InvalidOperationException: An exception occurred while reading a database value for property
A database operation failed while processing the request. SqlException: Invalid object name
InvalidOperationException: No database provider has been configured for this dbContext
NullReferenceException: Object reference not set to an instance of an object.
InvalidOperationException: The expected type was System.Boolean but the actual value was null.


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