EF Core Migration error: "Unable to create an object of type 'ApplicationContext'"

EF Core migrations using asp.net core, SQL Server and Docker yields dotnet SDK error

microsoft/aspnetcore:1.1.0... your are using is based on ...microsoft/dotnet:1.1.0-runtime.... It contains only .NET Core runtime, not SDK. To execute commands like ...run..., ...ef... and other tools - you need ...one of ...sdk...-based images

Entityframework Core Unable to cast object of type 'System.Int32' to type 'System.Int64'

It was my mistake.. When I first created the table, productNo was bigint and I created the model based on that table. After that somehow (it must be me...) productNo changed to int. It is working just fine after changing productNo back to bigint

EF Core Migration Error "Could not drop constraint" which was removed in previous migration

It looks like you may be hitting issue ...#7535.... This will be fixed in version 2.0.0.

Add-Migration error with EF Core Owned type

In the mean time, you can use the fluent method to configure this....Remove the ...[Owned]... attributes from the data model...Configure the relationship by overriding the ...OnModelCreating... method on your ...ApplicationDbContext...protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); m...

ASP.NET Core 3.0 Error 'Unable to cast object of type' while Scaffolding Existing Database

This is a known issue in ...EFCore Preview 4..., which was targeted to be fixed in Preview 5. Having encountered this issue myself, I can confirm that updating to Preview 5, which leaves my .csproj references for EFCore looking like this:...<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.0.0-preview5.19227.1" /> <Package...

EF Core migration with SQLite database: unable to create object of type

I've probably found the solution. There is a nice explanation of what's happening under-the-hood while generating migrations in docs ...[here].... ...In my case, according to documentation, EF Core Tools are trying to create an instance of ...SQLite_DbContext... passing no parameters to the constructor. Such constructor wasn't present in my code, b...

EF Core migration error: Object reference not set to an instance of an object

There was an ...issue... with EF core which causes ...System.NullReferenceException... when you ...Add-Migration.......System.NullReferenceException: Object reference not set to an instance of an object. ...The reason issue occurs is when any of your entity configurations have ...HasComment... in it. It's fixed and will be available via EF core 3.1...

EF Core "no migrations found" despite Migrations folder containing migration files

It turns out this error was because of the lack of Designer.cs files. We deleted them due to ...the response in this post..., but EF was not able to find our migrations without them. If you plan on running your migrations in any other environments, don't delete your Designer files!

ASP.NET Core + Entity Framework Core + SQLite Creating initial migration throws error

I found that in the ...DataContext... I used the wrong parameter...public DataContext(DbContextOptions<DbContext> options) : base(options) {} ...should be...public DataContext(DbContextOptions<DataContext> options) : base(options) {} ...Migration executed as expected.

EF Core migration error with .NET Core Web API in Visual Studio Code

Thank you @sea_ocean ... You have to specify the startup project:...dotnet ef migrations add MigrationOne --startup-project ../Sample.API/Sample.API.csproj ...and then...dotnet ef database update --startup-project ../Sample.API/Sample.API.csproj ...You also need to install Microsoft.EntityFrameworkCore.Design to the startup project