Unable to create an object of type 'ApplicationDbContext'. For the different patterns supported at design time

I found the cause of this error could be multiple things in your code. For me at least, the best way was to add verbose in command.

With that will be able to understand what is the problem. the verbose will display all steps of the execution.

In visual studio use:

add-migration Added_something -verbose

For the CLI use:

dotnet ef migrations add Added_something  --verbose

This error can also occur if multiple startup projects is selected. I set my webproject to startup project and that solved the issue for me.

My problem was solved by installing Microsoft.EntityFrameworkCore.Design nuget package.

this package is required for the Entity Framework Core Tools to work. Ensure your startup project is correct.then install the package.

at the end Build -> Clean Solution in your project and then try running your command again.

Help Link

add migration command cli:

dotnet ef migrations add InitDatabase --project YourDataAccessLibraryName -s YourWebProjectName -c YourDbContextClassName --verbose 

update database command cli:

dotnet ef database update InitDatabase --project YourDataAccessLibraryName -s YourWebProjectName -c YourDbContextClassName --verbose

remove migration command cli:

dotnet ef migrations remove --project YourDataAccessLibraryName -s YourWebProjectName -c YourDbContextClassName --verbose

Entity Framework Core tools reference - .NET Core CLI

I also had same problem today when I was running the dotnet ef migrations add <MigrationName>

I had three project, MainApp (Web), C# Project with DBContext and C# Project for Models.

I was able to resolve it from CLI.

dotnet ef migrations add AddCategoryTableToDb -s MainApp -p ProjectHavingDbContext

This error also can occur if you remove the static IHostBuilder CreateHostBuilder(string[] args) method from Program.cs for your .net core app. (This was my case)