Entity Framework Core - Migration - No Parameterless Constructor Defined for this Object
Design-time tools attempt to automatically find how your application creates instances of your DbContext type. If EF cannot find a suitable way to initialize your DbContext, you may encounter this error.
Options: 1- Either create a parameterless constructor
public AlmanacDb() { }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer(_connString);
}
private readonly string _connString = "<your conn string>";
2-
public AlmanacDb Create()
{
var optionsBuilder = new DbContextOptionsBuilder<AlmanacDb>();
optionsBuilder.UseSqlServer(connectionString);
return new AlmanacDb(optionsBuilder.Options);
}
https://docs.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext
If you have a separate project for context. set a startup project with the target project
dotnet ef migrations add InitialCreate -s .\src\WebUI\ -p .\src\Infrastructure\ --verbose