ASP.NET Core 6启动报错无法解析EFContext导致服务构造失败如何解决

启动应用时抛出如下聚合异常：

System.AggregateException: 'Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Data.Access.Layer.Interfaces.IUnitOfWork Lifetime: Scoped ImplementationType: Data.Access.Layer.Repositories.UnitOfWork': Unable to resolve service for type 'Data.Access.Layer.EFContext' while attempting to activate 'Data.Access.Layer.Repositories.UnitOfWork'.)'

相关实现代码：

// IUnitOfWork接口定义
public interface IUnitOfWork: IDisposable 
{
        IGenericRepository<ApplicationUser> Users { get; }
        IGenericRepository<Painting> Paintings { get; }
        IGenericRepository<OrderItem> OrdersItems { get; }
        IGenericRepository<Order> Orders { get; }
        IGenericRepository<ShoppingCartItem> ShoppingCartItems { get; }
}

// UnitOfWork实现
public class UnitOfWork : IUnitOfWork
{
        private readonly EFContext _eFContext;

        private GenericRepository<ApplicationUser> _users;
        private GenericRepository<Painting> _paintings;
        private GenericRepository<Order> _orders;
        private GenericRepository<OrderItem> _ordersItems;
        private GenericRepository<ShoppingCartItem> _shoppingCartItems;

        public UnitOfWork(EFContext eFContext)
        {
            _eFContext = eFContext;
        }

        public IGenericRepository<ApplicationUser> Users => _users ??= new GenericRepository<ApplicationUser>(_eFContext);
        public IGenericRepository<Painting> Paintings => _paintings ??= new GenericRepository<Painting>(_eFContext);
        public IGenericRepository<Order> Orders => _orders??= new GenericRepository<Order>(_eFContext);
        public IGenericRepository<OrderItem> OrdersItems => _ordersItems ??= new GenericRepository<OrderItem>(_eFContext);
        public IGenericRepository<ShoppingCartItem> ShoppingCartItems => _shoppingCartItems ??= new GenericRepository<ShoppingCartItem>(_eFContext);

        private bool disposed = false;

        public virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                   _eFContext.Dispose();
                }
                this.disposed = true;
            }
        }

        void IDisposable.Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
}

Program.cs配置代码：

using AutoMapper;
using Business.Layer.Interfaces;
using Business.Layer.Services;
using Data.Access.Layer.Entities;
using Data.Access.Layer.Interfaces;
using Data.Access.Layer.Repositories;
using Presentation.Layer.Mapping;

var builder = WebApplication.CreateBuilder(args);

// 向依赖注入容器添加服务
builder.Services.AddScoped<IUnitOfWork, UnitOfWork>();

builder.Services.AddRazorPages();
builder.Services.AddControllersWithViews();
builder.Services.AddAutoMapper(typeof(AutoMapperProfile).Assembly, typeof(BLAutoMapperProfile).Assembly);
var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");
app.UseRouting();
app.UseAuthorization();

app.MapRazorPages();

app.Run();

依赖注入容器在实例化UnitOfWork时，需要注入其构造函数依赖的EFContext类型，但你没有将EFContext注册到DI服务容器中，导致容器无法解析该依赖，最终抛出服务构造失败的异常。

• 确认项目已安装对应数据库提供程序的EF Core相关NuGet包，例如使用SQL Server需安装Microsoft.EntityFrameworkCore.SqlServer。
• 检查EFContext类的构造函数是否符合DI注入要求，正确写法如下：

public class EFContext : DbContext
{
    public EFContext(DbContextOptions<EFContext> options) : base(options)
    {
    }
    // 定义你的实体DbSet属性
    public DbSet<ApplicationUser> ApplicationUsers { get; set; }
    public DbSet<Painting> Paintings { get; set; }
    public DbSet<Order> Orders { get; set; }
    public DbSet<OrderItem> OrderItems { get; set; }
    public DbSet<ShoppingCartItem> ShoppingCartItems { get; set; }
}

• 在Program.cs的服务注册阶段（builder.Build()调用之前），使用AddDbContext方法注册EFContext，生命周期保持默认的Scoped即可，和UnitOfWork生命周期匹配不会出现冲突。修改后的服务注册部分代码如下：

var builder = WebApplication.CreateBuilder(args);

// 向依赖注入容器添加服务
// 注册EFContext数据库上下文，根据你使用的数据库替换对应提供程序方法和连接字符串配置
builder.Services.AddDbContext<EFContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddScoped<IUnitOfWork, UnitOfWork>();

builder.Services.AddRazorPages();
builder.Services.AddControllersWithViews();
builder.Services.AddAutoMapper(typeof(AutoMapperProfile).Assembly, typeof(BLAutoMapperProfile).Assembly);
var app = builder.Build();

// 其余中间件配置无需修改

注意：如果你使用的不是SQL Server数据库，将UseSqlServer替换为对应数据库的配置方法即可，例如SQLite使用UseSqlite、MySQL使用UseMySql，同时确保appsettings.json中已经配置了正确的数据库连接字符串。

内容的提问来源于stack exchange，提问作者user19300576