ASP.NET Core DbContext injection

Question

I have a ConfigurationDbContext that I am trying to use. It has multiple parameters, DbContextOptions and ConfigurationStoreOptions.

How can I add this DbContext to my services in ASP.NET Core?

I have attempted the following in my Startup.cs:

ConfigureServices .... services.AddDbContext<ConfigurationDbContext>(BuildDbContext(connString)); .... private ConfigurationDbContext BuildDbContext(string connString) { var builder = new DbContextOptionsBuilder<ConfigurationDbContext>(); builder.UseSqlServer(connString); var options = builder.Options; return new ConfigurationDbContext(options, new ConfigurationStoreOptions()); }

yes. But, to construct the dbcontext, I require to pass another parameter to it. — blgrnboy
– blgrnboy, Commented Jun 9, 2017 at 22:05

Ilya Chumakov · Accepted Answer · 2019-01-29 16:20:23Z

AddDbContext implementation just registers the context itself and its common dependencies in DI. Instead of AddDbContext call, it's perfectly legal to manually register your DbContext:

services.AddTransient<FooContext>();

Moreover, you could use a factory method to pass parameters (this is answering the question):

services.AddTransient<FooContext>(provider => { //resolve another classes from DI var anyOtherClass = provider.GetService<AnyOtherClass>(); //pass any parameters return new FooContext(foo, bar); });

P.S., In general, you don't have to register DbContextOptionsFactory and default DbContextOptions to resolve DbContext itself, but it could be necessary in specific cases.

Broken link - this is the file github.com/aspnet/EntityFrameworkCore/blob/master/src/EFCore/…
@Simon_Weaver thanks, I've updated the link. DbContextPool is something added in Core 2.0 I guess.
What would it look like for a generic context using a repository pattern?

hasan · Accepted Answer · 2017-06-09 22:02:48Z

You can use this in startup.cs.

Detail information : https://learn.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext

Detail Example : Getting started with ASP.NET Core MVC and Entity Framework Core

public void ConfigureServices(IServiceCollection services) { // Add framework services. services.AddDbContext<ApplicationDbContext>(options =>options. UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))); }

Vahid Farahmandian · Accepted Answer · 2019-02-17 14:41:22Z

In order to register DbContext as a service in IServiceCollection you have two options:(we assume that you are going to connect to a SQL Server database)

Using AddDbContext<>

services.AddDbContext<YourDbContext>(o=>o.UseSqlServer(Your Connection String));

Using AddDbContextPool<>

services.AddDbContextPool<YourDbContext>(o=>o.UseSqlServer(Your Connection String));

as you might see these two are in terms of writing have similarities, but in fact they have some fundamental differences in terms of concepts. @GabrielLuci has a nice response about the differences between these two: https://stackoverflow.com/a/48444206/1666800

Also note that you can store your connection string inside the appsettings.json file and simply read it using: Configuration.GetConnectionString("DefaultConnection") inside the ConfigureServices method in Startup.cs file.

I have a question. If I add dbcontext in StartUp.cs, do I have to use AddSingleton or 'AddScoped` or AddTransient etc?
@Hello starting with .NET core 2.0 by using AddDbContextPool you do not need to use AddTransient or AddSingleton or AddScoped methods. Read these for more info: stackoverflow.com/a/44484724/1666800 , stackoverflow.com/questions/48443567/…
Thanks for your kindly reply, I don't use AddDbContextPool. I just use AddDbContext. Because I followed an example at here, it doesn't use this kind of things, I don't understand it.
@Hello nice. you can read more about these two function here: learn.microsoft.com/en-us/dotnet/api/… , learn.microsoft.com/en-us/dotnet/api/…

hossein sedaghat · Accepted Answer · 2018-08-05 08:41:00Z

Try this for inject your ef context - context inheritance from IDbContext

1-Add your context to service:

 public void ConfigureServices(IServiceCollection services) { services.AddDbContext<NopaDbContext>( options => options .UseLazyLoadingProxies() .UseSqlServer(Configuration.GetConnectionString("NopaDbContext")),ServiceLifetime.Scoped);}

2-Inject your context:

 private readonly IDbContext _context; public EfRepository(NopaDbContext context) { this._context = context; } protected virtual DbSet<TEntity> Entities { get { if (_entities == null) _entities = _context.Set<TEntity>(); return _entities; } }

FindOutIslamNow · Accepted Answer · 2019-03-27 07:52:32Z

You can put all your parameters of db context in a class AppDbContextParams and register a factory to create that object for appdbcontext:

services.AddScoped(sp => { var currentUser = sp.GetService<IHttpContextAccessor>()?.HttpContext?.User?.Identity?.Name; return new AppDbContextParams { GetCurrentUsernameCallback = () => currentUser ?? "n/a" }; });

Simon_Weaver · Accepted Answer · 2021-11-10 00:27:18Z

EF Core 6 / .NET 6 has some changes to make it easier (and supported) to register DbContext and DbContextPool at the same time for different usages.

https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-6.0/whatsnew#dbcontext-factory-improvements

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