Migration using ef6.exe error: Value cannot be NULL. Parameter name: path1

Question

I'm trying to migrate from CLI using ef6.exe, but I keep getting the error, and I can't figure out what I'm missing, since database update works just fine. I have two contexts with different configurations. I tried expicitly the connection string, and getting it from web.config, neither helped.

Scaffolding migration 'testMigration'.
System.ArgumentNullException: Value cannot be NULL.
Parameter name: path1
   at: System.IO.Path.Combine(String path1, String path2)
   at: System.Data.Entity.Tools.Commands.ProjectCommandBase.WriteMigration(ScaffoldedMigration scaffoldedMigration, Boolean rescaffolding, Boolean force, String name)
   at: System.Data.Entity.Tools.Commands.MigrationsAddCommand.Execute()
   at: Microsoft.DotNet.Cli.CommandLine.CommandLineApplication.Execute(String[] args)
   at: System.Data.Entity.Tools.Program.Main(String[] args)
Value cannot be NULL.
Parameter name: path1

The command I'm using:

ef6.exe migrations add testMigration --migrations-config MyConfiguration --assembly MyAssembly.dll --connection-string-name “MyConnection” --config ..\Web.config --verbose  

Answer 1

You need to specify a value for the --project-dir parameter. This is partly because it needs to know where to save the generated files.