entity-framework-core

问题 I am trying to upgrade our current .Net Core application from 1.1 to 2.0 and am getting this runtime error: "The DbContext of type 'CoreContext' cannot be pooled because it does not have a single public constructor accepting a single parameter of type DbContextOptions". It is caused by using the new IServiceCollection.AddDbContextPool<> function. When I use IServiceCollection.AddDbContext<> it still works. This application is DB-First, so I generate all our contexts using 'Scaffold-DbContext'

问题 I am probably not thinking in the right direction. I am fairly new to Dependency Injection and ASP.Net Core. I have a ASP.Net core website, and one of the tasks is to import data from an excel sheet to a database that a user will upload. The excel sheets can be huge and the data transformation tasks are time taking, hence I wish to perform them in the background. i.e. The user will upload the sheet, the response will be sent immediately and the background job/thread will import the data. I am

问题 I'm creating a server side Blazor app. The following code is in the Startup.cs . services.AddDbContext<MyContext>(o => o.UseSqlServer(Configuration.GetConnectionString("MyContext")), ServiceLifetime.Transient); services.AddTransient<MyViewModel, MyViewModel>(); And in the ViewModel: public class MyViewModel : INotifyPropertyChanged { public MyViewModel(MyContext referenceContext) { _myContext = myContext; } public async Task<IEnumerable<Dto>> GetList(string s) { return await _myContext.Table1

问题 I'm creating a server side Blazor app. The following code is in the Startup.cs . services.AddDbContext<MyContext>(o => o.UseSqlServer(Configuration.GetConnectionString("MyContext")), ServiceLifetime.Transient); services.AddTransient<MyViewModel, MyViewModel>(); And in the ViewModel: public class MyViewModel : INotifyPropertyChanged { public MyViewModel(MyContext referenceContext) { _myContext = myContext; } public async Task<IEnumerable<Dto>> GetList(string s) { return await _myContext.Table1

问题 I have done scaffolding of my SQLServer database. And it creates the POCO objects in the specified folder. What i would like to do is that it extends from my base class. I also use repository pattern so i need to have Id key on every entity and I don't want to change that each time i rescaffold the database. Scaffold Model Example public partial class Food { public int Id { get; set; } public string Name { get; set; } public string Description { get; set; } public double Price { get; set; } }

问题 I'm building a multi-tenant application, and am running into difficulties with what I think is EF Core caching the tenant id across requests. The only thing that seems to help is constantly rebuilding the application as I sign in and out of tenants. I thought it may have something to do with the IHttpContextAccessor instance being a singleton, but it can't be scoped, and when I sign in and out without rebuilding I can see the tenant's name change at the top of the page, so it's not the issue.

问题 My problem is i am trying to seed an Entity Framework Core database with data and in my mind the below code show work. I've realised that this should not be called in the ApplicationDbContext constructor and should be called from the startup but im not sure how to do this. EDIT: Based on the solution provided by Ketrex, my solution is as follows: Startup.cs: public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) { ... app.ApplicationServices

问题 I need an ObservableCollection<TEntity> in EF7, DbSet<TEntity>.Local doesn't seem to exist; Is there any workaround? 回答1: Current version of EntityFramework (RC1-final) has no DbSet.Local feature. But! You can achieve something similar with current extension method: public static class Extensions { public static ObservableCollection<TEntity> GetLocal<TEntity>(this DbSet<TEntity> set) where TEntity : class { var context = set.GetService<DbContext>(); var data = context.ChangeTracker.Entries

问题 I am using Entity Framework 7 on the nightly build channel (right now I'm using version EntityFramework.7.0.0-beta2-11524) and I'm trying to log the queries that EF generates just out of curiosity. I'm writing a simple console program, I tried using the same logging technic that EF6 uses, but DbContext.Database.Log is not available on Entity Framework 7. Is there a way to log or just take a peek at the SQL generated by EF7? 回答1: For those using EF7 none of the above worked for me. But this is

问题 Is there way that dependency injection can be configured/bootstrapped when using Entity Framework's migration commands? Entity Framework Core supports dependency injection for DbContext subclasses. This mechanism includes allowing for configuration of data access outside of of the DbContext . For example, the following would configure EF to persist to a SQL server using a connection string retrieved from config.json ServiceCollection services = ... var configuration = new Configuration()