ASP .NET Core Publish Errors AddDbContext - asp.net

Question

i actually dont know deploy IIS for LAN server. We are working on this project together with my friend. We share same Wifi. So we want shared api project. Because i working on backend (API-DAL-BLL) layers, my friends working on FrontEnd. But i cant deploy very well.
First my publish cant see my DBContext.So i added Startup addDbContext.
My Startup.cs like this
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<GastroDB>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
services.AddScoped<IMainCategoryService, MainCategoryService>();
}
My Program.cs like this
public static void Main(string[] args)
{
CreateHostBuilder(args).Build().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseKestrel().UseContentRoot(Directory.GetCurrentDirectory()).UseUrls("myIpAdress:80").UseIISIntegration().UseStartup<Startup>();
});
}
But iis can not get start. This is my errors ;
.Net Runtime:
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ArgumentException: 'AddDbContext' was called with configuration, but the context type 'GastroDB' only declares a parameterless constructor. This means that the configuration passed to 'AddDbContext' will never be used. If configuration is passed to 'AddDbContext', then 'GastroDB' should declare a constructor that accepts a DbContextOptions<GastroDB> and must pass it to the base constructor for DbContext.
2)IIS AspNetCore Module V2
Application '/LM/W3SVC/1/ROOT' with physical root 'C:\Users\Tuğçe\Desktop\almanya projesi BE\EcommerceGastro.API\bin\Release\net5.0\publish\' hit unexpected managed exception, exception code = '0xe0434352'. First 30KB characters of captured stdout and stderr logs:
Unhandled exception. System.ArgumentException: 'AddDbContext' was called with configuration, but the context type 'GastroDB' only declares a parameterless constructor. This means that the configuration passed to 'AddDbContext' will never be used. If configuration is passed to 'AddDbContext', then 'GastroDB' should declare a constructor that accepts a DbContextOptions<GastroDB> and must pass it to the base constructor for DbContext.
I understand i will shoul add my context constructor like this
public GastroDB(DbContextOptions<GastroDB> options):base(options){}
But i cant add because first start like that on DBContext:
public class GastroDB : DbContext
{
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("server=.; database=GastroDB; user id=sa; password=123;");
}
private static GastroDB _dbInstance;
public static GastroDB DBInstance
{
get
{
if (_dbInstance == null)
{
_dbInstance = new GastroDB();
}
return _dbInstance;
}
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfiguration(new MyMap());
...
}
public DbSet<MyClass> MyClass{ get; set; }
....
}
}
If i add ctor on this code, my some services throw exeption because i use like this
using (var transaction = new GastroDB())
{
var productList = transaction.Set<DBProduct>().Include(x => x.ProductImage).ToList();
return this.mapper.Map<List<Product>>(productList);
}
How can i fix this problems i dont know how. Please help me

Answer 1

You Should create a constructor that accept
DbContextOptions<GastroDB>.
You don't need to use public static GastroDB DBInstance because
DbContext are registerd as Scoped life time.
public class GastroDB : DbContext
{
public GastroDB(DbContextOptions<GastroDB> options)
: base(options)
{
}
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("server=.; database=GastroDB; user id=sa; password=123;");
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfiguration(new MyMap());
...
}
public DbSet<MyClass> MyClass{ get; set; }
....
}
}
3 . If you want your DbContext register as singleton lifetime you can use below code instead of create a static property in DbContext
services.AddDbContext<GastroDB>(options =>
{
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))
}, ServiceLifetime.Singleton);