Unable to create an object of type 'DbContext' in EF Core
Dung Do Tien Apr 19 2022 561
I am a newbie in .Net 6 and Entity Framework Core. I have created a small project and using code-first to help CRUD a table in MySql. I created a DBContext as below:
namespace MyFirstFE.Persistence.ConnectDatabase.Context
{
public class EcommerDbContext : DbContext
{
public EcommerDbContext(DbContextOptions<EcommerDbContext> options)
: base(options)
{
}
public virtual DbSet<NotifyHistory> Notifyhistory { get; set; }
public virtual DbSet<User> Users { get; set; }
public virtual DbSet<Product> Products { get; set; }
public virtual DbSet<OrderDetail> OrderDetails { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseMySQL("server=35.240.179.150;uid=dungdt;[email protected];database=googlenotification");
}
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
}
}
} However when add Migration I get an error : Unable to create an object of type 'EcommerDbContext'.
Unable to create an object of type 'EcommerDbContext'. For the different patterns supported at design time,
see https://go.microsoft.com/fwlink/?linkid=851728
It's to difficult to understand, anyone can explain to me?
I'm using VS 2022 & Window 11.
Thanks for any explaintation.
Have 1 answer(s) found.
- C0
Ciline Slim Apr 19 2022
I got same error with .Net 6 Entity Framework and very easy to solve by add more default contructor to your DBContext. See an example:
public class EcommerDbContext : DbContext { public EcommerDbContext() { } public EcommerDbContext(DbContextOptions<EcommerDbContext> options) : base(options) { } public virtual DbSet<NotifyHistory> Notifyhistory { get; set; } public virtual DbSet<User> Users { get; set; } public virtual DbSet<Product> Products { get; set; } public virtual DbSet<OrderDetail> OrderDetails { get; set; } protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { if (!optionsBuilder.IsConfigured) { optionsBuilder.UseMySQL("server=35.240.179.150;uid=dungdt;[email protected];database=googlenotification"); } } protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); } }I hope it'll solve issue for you.
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