如何在DbContext ()之后访问.NET核心6程序类中的builder.Build类？

Question

我有一个DbContext课程。我在我的program.cs文件中使用这个方法注册了这个类：

using BethanyPieShop.Models;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);
// Register depancies for data acess it is good to use add scoped
builder.Services.AddDbContext<AppDbContext>(options =>
   options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection"))
);
builder.Services.AddScoped<IPieRespository, MockPieRepository>();
builder.Services.AddScoped<ICatgeoryRepository, MockCategoryRepository>();
builder.Services.AddScoped<IPieRespository, PieRepository>();
builder.Services.AddScoped<ICatgeoryRepository, CategoryRepository>();

builder.Services.AddControllersWithViews();

var app = builder.Build();

app.UseDeveloperExceptionPage();
app.UseHsts();
app.UseStaticFiles();
app.UseRouting();

// this important:
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Pie}/{action=List}/{id?}");

var serviceDescriptor = builder.Services.Where(sd => sd.ServiceType.Name.Contains("AppDbContext")).FirstOrDefault();
serviceDescriptor.ServiceType.GetType().

// AppDbContext context = (AppDbContext)builder.Services[0];
DbInitializer.Seed((AppDbContext)serviceDescriptor);
app.Run();

现在，我有了另一个静态类，它请求DbContext。

这是我的班级：

namespace BethanyPieShop.Models
{
    public static class DbInitializer
    {
        public static void Seed(AppDbContext context)
        {
            //AppDbContext context = applicationBuilder.ApplicationServices.GetRequiredService<AppDbContext>();

            if (!context.Categories.Any())
            {
                context.Categories.AddRange(Categories.Select(c => c.Value));
            }

            if (!context.Pies.Any())
            {
                context.AddRange
                (
                    new Pie { Name = "Apple Pie", Price = 12.95M, ShortDescription = "Our famous apple pies!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Fruit pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/applepie.jpg", InStock = true, IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/applepiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Blueberry Cheese Cake", Price = 18.95M, ShortDescription = "You'll love it!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Cheese cakes"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/blueberrycheesecake.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/blueberrycheesecakesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Cheese Cake", Price = 18.95M, ShortDescription = "Plain cheese cake. Plain pleasure.", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Cheese cakes"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cheesecake.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cheesecakesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Cherry Pie", Price = 15.95M, ShortDescription = "A summer classic!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Fruit pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cherrypie.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cherrypiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Christmas Apple Pie", Price = 13.95M, ShortDescription = "Happy holidays with this pie!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Seasonal pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/christmasapplepie.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/christmasapplepiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Cranberry Pie", Price = 17.95M, ShortDescription = "A Christmas favorite", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Seasonal pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cranberrypie.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/cranberrypiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Peach Pie", Price = 15.95M, ShortDescription = "Sweet as peach", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Fruit pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/peachpie.jpg", InStock = false, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/peachpiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Pumpkin Pie", Price = 12.95M, ShortDescription = "Our Halloween favorite", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Seasonal pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/pumpkinpie.jpg", InStock = true, IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/pumpkinpiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Rhubarb Pie", Price = 15.95M, ShortDescription = "My God, so sweet!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Fruit pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/rhubarbpie.jpg", InStock = true, IsPieOfTheWeek = true, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/rhubarbpiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Strawberry Pie", Price = 15.95M, ShortDescription = "Our delicious strawberry pie!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Fruit pies"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrypie.jpg", InStock = true, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrypiesmall.jpg", AllergyInformation = "" },
                    new Pie { Name = "Strawberry Cheese Cake", Price = 18.95M, ShortDescription = "You'll love it!", LongDescription = "Icing carrot cake jelly-o cheesecake. Sweet roll marzipan marshmallow toffee brownie brownie candy tootsie roll. Chocolate cake gingerbread tootsie roll oat cake pie chocolate bar cookie dragée brownie. Lollipop cotton candy cake bear claw oat cake. Dragée candy canes dessert tart. Marzipan dragée gummies lollipop jujubes chocolate bar candy canes. Icing gingerbread chupa chups cotton candy cookie sweet icing bonbon gummies. Gummies lollipop brownie biscuit danish chocolate cake. Danish powder cookie macaroon chocolate donut tart. Carrot cake dragée croissant lemon drops liquorice lemon drops cookie lollipop toffee. Carrot cake carrot cake liquorice sugar plum topping bonbon pie muffin jujubes. Jelly pastry wafer tart caramels bear claw. Tiramisu tart pie cake danish lemon drops. Brownie cupcake dragée gummies.", Category = Categories["Cheese cakes"], ImageUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrycheesecake.jpg", InStock = false, IsPieOfTheWeek = false, ImageThumbnailUrl = "https://gillcleerenpluralsight.blob.core.windows.net/files/strawberrycheesecakesmall.jpg", AllergyInformation = "" }
                );
            }

            context.SaveChanges();

现在在我的节目课上，我打电话给

DbInitializer.Seed((AppDbContext)serviceDescriptor)；

如果我在建筑工地上搜索我所有的注册服务。

我可以找到DbContext类的服务描述符：

var serviceDescriptor = builder.Services.Where(sd => sd.ServiceType.Name.Contains("AppDbContext")).FirstOrDefault();

Answer 1

在我的单元测试中，我经常需要像你展示的那样获得服务。显然，没有两个类包含名称AppDbContext，因此由于某种原因，它没有正确地获得服务。这就是我使用IWebHostEnvironment的方法，您可以尝试类似的方法：

public UnitTests()
{
    var builder = WebApplication.CreateBuilder();
    var app = builder.Build();
    _serviceProvider = new DependencyResolverHelper(app);

    env = _serviceProvider.GetService<IWebHostEnvironment>();
    AppDomain.CurrentDomain.SetData("ContentRootPath", env.ContentRootPath);
    AppDomain.CurrentDomain.SetData("WebRootPath", env.WebRootPath);
}

依赖帮助类：

public class DependencyResolverHelper
{
    private readonly WebApplication _webApp;

    public DependencyResolverHelper(WebApplication webApp) => _webApp = webApp;

    private IServiceScope serviceScope;

    public T GetService<T>()
    {
        try
        {
            serviceScope = _webApp.Services.CreateScope();
            var services = serviceScope.ServiceProvider;
            var scopedService = services.GetRequiredService<T>();
            return scopedService;
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }

    public void DisposeServiceScope()
    {
        if (serviceScope != null) serviceScope.Dispose();
    }
}

}