Cannot create controller with Entity framework - Unable to retrieve metadata

问题

I'm using VS2013

When I try to create an "MVC 5 Controller with views using entity Framework" I get the following error:

there was an error running the selected code generator ''Unable to retrieve metadata for WebApplication.Domain.Entities.Product'.'

EFDbContext.cs

using System.Data.Entity;
using WebApplication.Domain.Entities;

namespace WebApplication.Domain.Concrete
{
    public class EFDbContext : DbContext
    {
        public DbSet<Product> Products;
    }
}

Product.cs

using System.ComponentModel.DataAnnotations;

namespace WebApplication.Domain.Entities
{
    public class Product
    {
        [Key]
        public int ProductID { get; set; }

        [Required]
        public string Title { get; set; }
    }
}

Web.config

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=301880
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <connectionStrings>
    <add name="EFDbContext" connectionString="Data Source=(LocalDB)\v11.0;Initial Catalog=WebApplication;Integrated Security=True" providerName="System.Data.SqlClient"/>
  </connectionStrings>
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
  </system.web>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
</configuration>

I have a Table set up called Products and it has a definition like so:

CREATE TABLE [dbo].[Products] (
    [ProductID] INT            IDENTITY (1, 1) NOT NULL,
    [Title]     NVARCHAR (255) NULL,
    PRIMARY KEY CLUSTERED ([ProductID] ASC)
);

Any ideas what is going wrong? I have tried everything that has returned on Google.

Packages I have installed:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="6.0.1" targetFramework="net45" />
  <package id="jQuery" version="1.10.2" targetFramework="net45" />
  <package id="jQuery.Validation" version="1.11.1" targetFramework="net45" />
  <package id="Microsoft.AspNet.Mvc" version="5.0.0" targetFramework="net45" />
  <package id="Microsoft.AspNet.Razor" version="3.0.0" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebPages" version="3.0.0" targetFramework="net45" />
  <package id="Microsoft.jQuery.Unobtrusive.Validation" version="3.0.0" targetFramework="net45" />
  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" targetFramework="net45" />
  <package id="Unity" version="3.0.1304.1" targetFramework="net45" />
  <package id="Unity.Mvc" version="3.0.1304.0" targetFramework="net45" />
  <package id="WebActivatorEx" version="2.0.4" targetFramework="net45" />
</packages>

My project can be found here: https://github.com/jimmyt1988/WebApplication2

回答1:

public class EFDbContext : DbContext
{
    public DbSet<Product> Products { get; set; }
}

Forgot the { get; set; }... all works now #crying

回答2:

Problem may be because of missing [NotMapped] Attribute in one of the model class.

As I missed the attribute and I was cunning my head.

[Display(Name="Logo")]
[DataType(DataType.Upload)]
[NotMapped]
public HttpPostedFileBase Logo { set; get; }

回答3:

Please check all the Models are registered in context

Example:

You have a Model like this

public class MedicineStrength
{
    [Key]
    public int Id { get; set; }
    public int? MedicineId { get; set; }
    [ForeignKey("MedicineId")]
    public Medicine Medicine { get; set; }

    public double Strength { get; set; }

    public int? MetricPrefixId { get; set; }
    [ForeignKey("MetricPrefixId")]
    public virtual MetricPrefix MetricPrefix { get; set; }

    public int? UnitId { get; set; }
    [ForeignKey("UnitId")]
    public virtual Unit Unit { get; set; }

    public int? MedicineTypeId { get; set; }
    [ForeignKey("MedicineTypeId")]
    public virtual MedicineType MedicineType { get; set; }
}

Check all virtual Model instances are registered in in context like this

public class HMContext : DbContext
    {
        public HMContext()
        : base("name=HMContext")
        {
            Database.SetInitializer<HMContext>(null);
        }

        /// ... ///

        public virtual DbSet<Medicine> Medicines { get; set; }
        public virtual DbSet<MedicineGeneric> MedicineGenerics { get; set; }
        public virtual DbSet<MedicineStrength> MedicineStrengths { get; set; }
        public virtual DbSet<MedicineType> MedicineTypes { get; set; }
        public virtual DbSet<MedicineDosage> MedicineDosages { get; set; }
        public virtual DbSet<MedicineCategory> MedicineCategories { get; set; }
        public virtual DbSet<MetricPrefix> MetricPrefixes { get; set; }
        public virtual DbSet<Unit> Units { get; set; }

        ///...///
    } 

回答4:

Re-Try after deleting below line from your EFDbContext class.

public System.Data.Entity.DbSet<WebApplication.Domain.Entities.Product> Products { get; set; }

Example:

回答5:

In my case, but using VS 2017, this occurred when I had all my model classes defined within a single .cs file. Once I separated each class out into its own file the generation process completed correctly.

回答6:

If you trying to create a Odata controller

Go to DbContext class and then check whether

public System.Data.Entity.DbSet<BackEnd.Models.OrganizationType> YourModel{ get; set; }

Available ior not

If yes .. remove it and then retry

回答7:

For me, I have to "run custom tool" by right click on model.tt and model.context.tt files, then error got resolved.

来源：https://stackoverflow.com/questions/20482053/cannot-create-controller-with-entity-framework-unable-to-retrieve-metadata