生成Razor视图时遇DbContextOptions服务解析错误求助

尝试通过Scaffold生成Razor视图时出现错误：

无法解析类型为'Microsoft.EntityFrameworkCore.DbContextOptions`1[DonnaPerfum.DataAccess.Data.ApplicationDbContext]'的服务，尝试激活'DonnaPerfum.DataAccess.Data.ApplicationDbContext'时出错。

相关代码 #

Program.cs 配置代码 #

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddMvc();
builder.Services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddDatabaseDeveloperPageExceptionFilter();
builder.Services.AddDefaultIdentity<IdentityUser>(options=> options.SignIn.RequireConfirmedAccount = true).AddEntityFrameworkStores<ApplicationDbContext>();
builder.Services.AddScoped<IUnitOfWork, UnitOfWork>();
builder.Services.AddControllers();
builder.Services.AddControllersWithViews();

builder.Services.AddRazorPages().AddRazorRuntimeCompilation();
var app = builder.Build();

ApplicationDbContext 代码 #

using Donna.Models;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;

namespace DonnaPerfum.DataAccess.Data
{
public class ApplicationDbContext : IdentityDbContext
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options):base(options)
{
}
public DbSet<Category> Categories { get; set; }
}
}

该错误是因为Scaffold设计时工具无法自动获取DbContext的配置，需添加设计时工厂类来解决：

• 在DonnaPerfum.DataAccess.Data命名空间下新增实现IDesignTimeDbContextFactory<ApplicationDbContext>的类：

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.Extensions.Configuration;
using System.IO;

namespace DonnaPerfum.DataAccess.Data
{
    public class ApplicationDbContextFactory : IDesignTimeDbContextFactory<ApplicationDbContext>
    {
        public ApplicationDbContext CreateDbContext(string[] args)
        {
            IConfigurationRoot configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json")
                .Build();

            var optionsBuilder = new DbContextOptionsBuilder<ApplicationDbContext>();
            var connectionString = configuration.GetConnectionString("DefaultConnection");
            optionsBuilder.UseSqlServer(connectionString);

            return new ApplicationDbContext(optionsBuilder.Options);
        }
    }
}

• 确认appsettings.json中存在正确的DefaultConnection连接字符串，示例格式：

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=你的服务器名;Database=你的数据库名;Trusted_Connection=True;TrustServerCertificate=True;"
  }
}

• 重新运行Scaffold命令即可。

注：你的Program.cs中已正确注册DbContext服务，但设计时工具不会直接复用该配置，必须通过工厂类提供设计时的DbContext实例。

内容的提问来源于stack exchange，提问作者Razor