Question

我正在使用Visual Studio Community 2015 v 14.0.25431.01 Update 3和MS .NET Framework v 4.6.91586关注this tutorial，但是当我尝试搭建控制器时出现以下错误，如下所述：< / p>

我已经尝试了所有建议的解决方案here和here，但无济于事。是的，也尝试（重新）建立项目。

以下是我项目的相关代码。

学生模特：

using System;
using System.Collections.Generic;

namespace ContosoUniversity.Models
{
    public class Student
    {
        public int ID { get; set; }
        public string LastName { get; set; }
        public string FirstMidName { get; set; }
        public DateTime EnrollmentDate { get; set; }

        public ICollection<Enrollment> Enrollments { get; set; }
    }
}

SchoolContext：

public class SchoolContext : DbContext
    {
        public SchoolContext(DbContextOptions<SchoolContext> options) : base(options)
        {
        }

        public DbSet<Course> Courses { get; set; }
        public DbSet<Enrollment> Enrollments { get; set; }
        public DbSet<Student> Students { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Course>().ToTable("Course");
            modelBuilder.Entity<Enrollment>().ToTable("Enrollment");
            modelBuilder.Entity<Student>().ToTable("Student");
        }

    }

将SchoolContext添加到startup.cs中的服务：

public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddApplicationInsightsTelemetry(Configuration);

            services.AddDbContext<SchoolContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

这是我在appSetting.json中的连接字符串：

"ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-ContosoUniversity-75b88406-9d10-4237-814a-3f725b9b4e3d;Trusted_Connection=True;MultipleActiveResultSets=true"
  }

Answer 1

好的，所以我设法克服了没有无参数构造函数的问题。正如建议here，我只是将构造函数提供给DBContext类以及Model类：

public Student() { }

现在我收到了一个不同的错误。我想我需要把它作为一个新问题。我会，但是为了它的价值，这是错误日志的一部分：

        Attempting to figure out the EntityFramework metadata for the model and DbContext: Student
    Exception has been thrown by the target of an invocation. StackTrace:
       at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
       at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
       at Microsoft.AspNetCore.Hosting.Internal.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder)
       at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()
       at Microsoft.AspNetCore.Hosting.WebHostBuilder.Build()
       at Microsoft.VisualStudio.Web.CodeGeneration.EntityFrameworkCore.EntityFrameworkServices.TryCreateContextUsingAppCode(Type dbContextType, ModelType startupType)
    A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 52 - Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.) StackTrace:
...
    System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
    There is no entity type Student on DbContext ContosoUniversity.Data.SchoolContext   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject,...

实体框架核心1.0不是脚手架控制器和视图

1 个答案: