数据库上下文错误的依赖注入

Question

您好，我正在尝试在 controller 的构造函数中创建一个数据库实例，以便能够在整个 controller 中使用它，但它一直抛出错误。

这是我得到的错误：

InvalidOperationException: Unable to resolve service for type 'Darkcrow_Dashboard.Model.ApplicationDbContext' while attempting to activate 'Darkcrow_Dashboard.Controllers.DashboardController'.

这是 applicationdbcontext.cs：

using System;
using System.Collections.Generic;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;

namespace Darkcrow_Dashboard.Model
{
    public partial class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext()
        {
        }

        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {
        }

        public virtual DbSet<Artifact> Artifacts { get; set; } = null!;
        public virtual DbSet<ArtifactSize> ArtifactSizes { get; set; } = null!;
        public virtual DbSet<AspNetRole> AspNetRoles { get; set; } = null!;
        public virtual DbSet<AspNetRoleClaim> AspNetRoleClaims { get; set; } = null!;
        public virtual DbSet<AspNetUser> AspNetUsers { get; set; } = null!;
        public virtual DbSet<AspNetUserClaim> AspNetUserClaims { get; set; } = null!;
        public virtual DbSet<AspNetUserLogin> AspNetUserLogins { get; set; } = null!;
        public virtual DbSet<AspNetUserToken> AspNetUserTokens { get; set; } = null!;
        public virtual DbSet<Dcplayer> Dcplayers { get; set; } = null!;
        public virtual DbSet<Dcvillage> Dcvillages { get; set; } = null!;
        public virtual DbSet<DefensiveForm> DefensiveForms { get; set; } = null!;
        public virtual DbSet<OtherPlayer> OtherPlayers { get; set; } = null!;
        public virtual DbSet<OtherVillage> OtherVillages { get; set; } = null!;
        public virtual DbSet<Vagon> Vagons { get; set; } = null!;

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
#warning To protect potentially sensitive information in your connection string, you should move it out of source code. You can avoid scaffolding the connection string by using the Name= syntax to read it from configuration - see https://go.microsoft.com/fwlink/?linkid=2131148. For more guidance on storing connection strings, see http://go.microsoft.com/fwlink/?LinkId=723263.
                optionsBuilder.UseSqlServer("Server=localhost\\SQLEXPRESS;Database=DarkCrow;Trusted_Connection=True;");
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Artifact>(entity =>
            {
                entity.HasKey(e => e.ArtifactName);

                entity.ToTable("Artifact");

                entity.Property(e => e.ArtifactName)
                    .HasMaxLength(45)
                    .IsUnicode(false);

                entity.HasMany(d => d.Sizes)
                    .WithMany(p => p.ArtifactNames)
                    .UsingEntity<Dictionary<string, object>>(
                        "ArtifactArtifactSize",
                        l => l.HasOne<ArtifactSize>().WithMany().HasForeignKey("Size").OnDelete(DeleteBehavior.ClientSetNull).HasConstraintName("FK_Multi_ArtifactSize_Artifact"),
                        r => r.HasOne<Artifact>().WithMany().HasForeignKey("ArtifactName").OnDelete(DeleteBehavior.ClientSetNull).HasConstraintName("FK_Multi_Artifact_ArtifactSize"),
                        j =>
                        {
                            j.HasKey("ArtifactName", "Size");

                            j.ToTable("Artifact_ArtifactSize");

                            j.IndexerProperty<string>("ArtifactName").HasMaxLength(45).IsUnicode(false);

                            j.IndexerProperty<string>("Size").HasMaxLength(10).IsUnicode(false);
                        });
            });

            modelBuilder.Entity<ArtifactSize>(entity =>
            {
                entity.HasKey(e => e.Size);

                entity.ToTable("ArtifactSize");

                entity.Property(e => e.Size)
                    .HasMaxLength(10)
                    .IsUnicode(false);
            });

            modelBuilder.Entity<AspNetRole>(entity =>
            {
                entity.HasIndex(e => e.NormalizedName, "RoleNameIndex")
                    .IsUnique()
                    .HasFilter("([NormalizedName] IS NOT NULL)");

                entity.Property(e => e.Name).HasMaxLength(256);

                entity.Property(e => e.NormalizedName).HasMaxLength(256);
            });

            modelBuilder.Entity<AspNetRoleClaim>(entity =>
            {
                entity.HasIndex(e => e.RoleId, "IX_AspNetRoleClaims_RoleId");

                entity.HasOne(d => d.Role)
                    .WithMany(p => p.AspNetRoleClaims)
                    .HasForeignKey(d => d.RoleId);
            });

            modelBuilder.Entity<AspNetUser>(entity =>
            {
                entity.HasIndex(e => e.NormalizedEmail, "EmailIndex");

                entity.HasIndex(e => e.NormalizedUserName, "UserNameIndex")
                    .IsUnique()
                    .HasFilter("([NormalizedUserName] IS NOT NULL)");

                entity.Property(e => e.Email).HasMaxLength(256);

                entity.Property(e => e.NormalizedEmail).HasMaxLength(256);

                entity.Property(e => e.NormalizedUserName).HasMaxLength(256);

                entity.Property(e => e.UserName).HasMaxLength(256);

                entity.HasMany(d => d.Roles)
                    .WithMany(p => p.Users)
                    .UsingEntity<Dictionary<string, object>>(
                        "AspNetUserRole",
                        l => l.HasOne<AspNetRole>().WithMany().HasForeignKey("RoleId"),
                        r => r.HasOne<AspNetUser>().WithMany().HasForeignKey("UserId"),
                        j =>
                        {
                            j.HasKey("UserId", "RoleId");

                            j.ToTable("AspNetUserRoles");

                            j.HasIndex(new[] { "RoleId" }, "IX_AspNetUserRoles_RoleId");
                        });
            });

            modelBuilder.Entity<AspNetUserClaim>(entity =>
            {
                entity.HasIndex(e => e.UserId, "IX_AspNetUserClaims_UserId");

                entity.HasOne(d => d.User)
                    .WithMany(p => p.AspNetUserClaims)
                    .HasForeignKey(d => d.UserId);
            });

            modelBuilder.Entity<AspNetUserLogin>(entity =>
            {
                entity.HasKey(e => new { e.LoginProvider, e.ProviderKey });

                entity.HasIndex(e => e.UserId, "IX_AspNetUserLogins_UserId");

                entity.Property(e => e.LoginProvider).HasMaxLength(128);

                entity.Property(e => e.ProviderKey).HasMaxLength(128);

                entity.HasOne(d => d.User)
                    .WithMany(p => p.AspNetUserLogins)
                    .HasForeignKey(d => d.UserId);
            });

            modelBuilder.Entity<AspNetUserToken>(entity =>
            {
                entity.HasKey(e => new { e.UserId, e.LoginProvider, e.Name });

                entity.Property(e => e.LoginProvider).HasMaxLength(128);

                entity.Property(e => e.Name).HasMaxLength(128);

                entity.HasOne(d => d.User)
                    .WithMany(p => p.AspNetUserTokens)
                    .HasForeignKey(d => d.UserId);
            });

            modelBuilder.Entity<Dcplayer>(entity =>
            {
                entity.ToTable("DCPlayer");

                entity.HasIndex(e => e.Username, "UQ__DCPlayer__536C85E41EFBF1E2")
                    .IsUnique();

                entity.Property(e => e.Id)
                    .ValueGeneratedNever()
                    .HasColumnName("ID");

                entity.Property(e => e.Username)
                    .HasMaxLength(20)
                    .IsUnicode(false);
            });

            modelBuilder.Entity<Dcvillage>(entity =>
            {
                entity.ToTable("DCVillage");

                entity.Property(e => e.Id)
                    .ValueGeneratedNever()
                    .HasColumnName("ID");

                entity.Property(e => e.DcplayerId).HasColumnName("DCPlayer_ID");

                entity.Property(e => e.VillageName)
                    .HasMaxLength(40)
                    .IsUnicode(false);

                entity.Property(e => e.Xcoordinate).HasColumnName("XCoordinate");

                entity.Property(e => e.Ycoordinate).HasColumnName("YCoordinate");

                entity.HasOne(d => d.Dcplayer)
                    .WithMany(p => p.Dcvillages)
                    .HasForeignKey(d => d.DcplayerId)
                    .HasConstraintName("FK_TEST");
            });

            modelBuilder.Entity<DefensiveForm>(entity =>
            {
                entity.HasKey(e => e.FormId)
                    .HasName("PK_formID");

                entity.ToTable("DefensiveForm");

                entity.Property(e => e.FormId).HasColumnName("formID");

                entity.Property(e => e.ArtifactName)
                    .HasMaxLength(45)
                    .IsUnicode(false)
                    .HasColumnName("Artifact_Name");

                entity.Property(e => e.CalculatedPt).HasColumnName("CalculatedPT");

                entity.Property(e => e.DcplayerId).HasColumnName("DCPlayer_ID");

                entity.Property(e => e.OtherPlayerId).HasColumnName("OtherPlayer_ID");

                entity.Property(e => e.Pt).HasColumnName("PT");

                entity.HasOne(d => d.ArtifactNameNavigation)
                    .WithMany(p => p.DefensiveForms)
                    .HasForeignKey(d => d.ArtifactName)
                    .OnDelete(DeleteBehavior.Cascade)
                    .HasConstraintName("FK_Artifact_DeffForm");

                entity.HasOne(d => d.Dcplayer)
                    .WithMany(p => p.DefensiveForms)
                    .HasForeignKey(d => d.DcplayerId)
                    .HasConstraintName("FK_DCPlayer_DeffForm");

                entity.HasOne(d => d.OtherPlayer)
                    .WithMany(p => p.DefensiveForms)
                    .HasForeignKey(d => d.OtherPlayerId)
                    .HasConstraintName("FK_OtherPlayer_DeffForm");
            });

            modelBuilder.Entity<OtherPlayer>(entity =>
            {
                entity.ToTable("OtherPlayer");

                entity.HasIndex(e => e.Username, "UQ__OtherPla__536C85E4BF7EA2E1")
                    .IsUnique();

                entity.Property(e => e.Id)
                    .ValueGeneratedNever()
                    .HasColumnName("ID");

                entity.Property(e => e.Alliance)
                    .HasMaxLength(10)
                    .IsUnicode(false);

                entity.Property(e => e.Username)
                    .HasMaxLength(20)
                    .IsUnicode(false);
            });

            modelBuilder.Entity<OtherVillage>(entity =>
            {
                entity.ToTable("OtherVillage");

                entity.Property(e => e.Id)
                    .ValueGeneratedNever()
                    .HasColumnName("ID");

                entity.Property(e => e.OtherPlayerId).HasColumnName("OtherPlayer_ID");

                entity.Property(e => e.VillageName)
                    .HasMaxLength(40)
                    .IsUnicode(false);

                entity.Property(e => e.Xcoordinate).HasColumnName("XCoordinate");

                entity.Property(e => e.Ycoordinate).HasColumnName("YCoordinate");

                entity.HasOne(d => d.OtherPlayer)
                    .WithMany(p => p.OtherVillages)
                    .HasForeignKey(d => d.OtherPlayerId)
                    .HasConstraintName("FK_Village_OtherPlayer");
            });

            modelBuilder.Entity<Vagon>(entity =>
            {
                entity.ToTable("Vagon");

                entity.Property(e => e.Id).HasColumnName("ID");

                entity.Property(e => e.DefensiveFormId).HasColumnName("DefensiveForm_ID");

                entity.Property(e => e.VagonTime).HasColumnType("datetime");

                entity.HasOne(d => d.DefensiveForm)
                    .WithMany(p => p.Vagons)
                    .HasForeignKey(d => d.DefensiveFormId)
                    .HasConstraintName("FK_DeffForm_Vagon");
            });

            OnModelCreatingPartial(modelBuilder);
        }

        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
    }
}

这是 controller 我想在其中注入数据库的依赖项

using Darkcrow_Dashboard.Model;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;

namespace Darkcrow_Dashboard.Controllers
{
    [Authorize]
    public class DashboardController : Controller
    {
        private readonly UserManager<IdentityUser> _userManager;
        private readonly ApplicationDbContext _db;

        public DashboardController(UserManager<IdentityUser> userManager, ApplicationDbContext db)
        {
            _userManager = userManager;
            _db = db;
        }

        public async Task<IActionResult> Index()
        {

            return View();
        }

        public IActionResult Defensivo()
        {
            return View();
        }

        public IActionResult Artefacto()
        {
            return View();
        }
    }
}

这是我的文件浏览器

这是完整的错误

Answer 1

看起来您的上下文未添加到 DI 容器中。

这是EntityFrameworkServiceCollectionExtensions.AddDbContext Method的片段：

 public void ConfigureServices(IServiceCollection services) { var connectionString = "connection string to database"; services.AddDbContext<MyContext>(options => >options.UseSqlServer(connectionString)); }

Answer 2

当您在 controller 中使用 UserManager 时，您必须从IdentityDbContext继承您的DBContext 。

public partial class ApplicationDbContext : IdentityDBContext<IdentityUser>

Answer 3

首先，将您的 Db 上下文添加到 startUp ConfigureServices 方法中，如“tymtam”所说，而不是像这样在 ConfigureServices 中注册您的身份：

services.AddIdentity<ApplicationUser, IdentityRole>();

而不是从 IdentityDbContext 继承您的上下文