Type Load Exception in EF Core Project

Question

I have an ASP.NET Core 3.1 Web API application using EF Core. This is the my configuration in the ConfigureServices method of the Startup class:

services.AddDbContext<ApplicationContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("AppConn")));

The above configuration tested and works for a SQL Server database.

Then I switched to using Sqlite after installing its package successfully.

services.AddDbContext<ApplicationContext>(options =>
     options.UseSqlite("Data Source=sqlitedemo.db"));

But when I try to add the EF migration

add-migration initial -context ApplicationContext

I get this error:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.

System.TypeLoadException: Could not load type 'Microsoft.EntityFrameworkCore.Internal.SemanticVersionComparer' from assembly 'Microsoft.EntityFrameworkCore, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.

{ Stack trace }

Exception has been thrown by the target of an invocation.

Answer 1

Please update to your entity framework core nuget package to 3.1.10(or latest 5.0.0). It will solve your problem.

Answer 2

I had EF Core 5 package installed, but not Microsoft.EntityFrameworkCore.Design and one package were implicitly referencing older version (Microsoft.EntityFrameworkCore.Design 3.0.0).

Installing explicit dependency on Microsoft.EntityFrameworkCore.Design 5.x.x resolved the issue for me.