EF4 POCO（不使用 T4）：找不到 EntityType 的映射和元数据信息

问题描述 投票：0回答：3

我有一个非常简单的控制台项目，其中包含一个实体模型（包含两个简单实体）、两个手工制作的 POCO 和一个手工制作的 Context 类。该程序对数据库触发一个简单的查询，包括 LazyLoading 在内的所有内容都工作正常。

问题：一旦我添加另一个实体数据模型（即使我添加一个空模型），对 Ef2PlaygroundModel_3Container 中的 CreateObjectSet 的调用就会抛出以下异常：

Unhandled Exception: System.InvalidOperationException: Mapping and metadata information could not be found for EntityType 'EF2_Playground.Driver'.
  at System.Data.Objects.ObjectContext.GetTypeUsage(Type entityCLRType)
  at System.Data.Objects.ObjectContext.GetEntitySetFromContainer(EntityContainer container, Type entityCLRType, String exceptionParameterName)
  at System.Data.Objects.ObjectContext.GetEntitySetForType(Type entityCLRType, String exceptionParameterName)
  at System.Data.Objects.ObjectContext.CreateObjectSet[TEntity]()
  at EF2_Playground.Ef2PlaygroundModel_3Container.get_Drivers() in C:\...\Ef2PlaygroundModel_3Pocos.cs:line 64
  at EF2_Playground.Program.Main(String[] args) in C:\...\Program.cs:line 15

有人知道这里出了什么问题吗？

这就是工作项目：

Ef2PlaygroundModel_3.edmx：

EF4 Data Model

代码生成策略设置为“无”

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="2.0" xmlns:edmx="http://schemas.microsoft.com/ado/2008/10/edmx">
  <!-- EF Runtime content -->
  <edmx:Runtime>
    <!-- SSDL content -->
    <edmx:StorageModels>
      <Schema Namespace="Ef2PlaygroundModel_3.Store" Alias="Self" Provider="System.Data.SqlClient" ProviderManifestToken="2008" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" xmlns="http://schemas.microsoft.com/ado/2009/02/edm/ssdl">
        <EntityContainer Name="Ef2PlaygroundModel_3StoreContainer">
          <EntitySet Name="Cars" EntityType="Ef2PlaygroundModel_3.Store.Cars" store:Type="Tables" Schema="dbo"/>
          <EntitySet Name="Drivers" EntityType="Ef2PlaygroundModel_3.Store.Drivers" store:Type="Tables" Schema="dbo"/>
          <EntitySet Name="CarDriver" EntityType="Ef2PlaygroundModel_3.Store.CarDriver" store:Type="Tables" Schema="dbo"/>
          <AssociationSet Name="FK_CarDriver_Car" Association="Ef2PlaygroundModel_3.Store.FK_CarDriver_Car">
            <End Role="Car" EntitySet="Cars"/>
            <End Role="CarDriver" EntitySet="CarDriver"/>
          </AssociationSet>
          <AssociationSet Name="FK_CarDriver_Driver" Association="Ef2PlaygroundModel_3.Store.FK_CarDriver_Driver">
            <End Role="Driver" EntitySet="Drivers"/>
            <End Role="CarDriver" EntitySet="CarDriver"/>
          </AssociationSet>
        </EntityContainer>
        <EntityType Name="Cars">
          <Key>
            <PropertyRef Name="Id"/>
          </Key>
          <Property Name="Id" Type="int" StoreGeneratedPattern="Identity" Nullable="false"/>
          <Property Name="Brand" Type="nvarchar(max)" Nullable="false"/>
          <Property Name="Model" Type="nvarchar(max)" Nullable="false"/>
          <Property Name="ReleaseDate" Type="datetime" Nullable="true"/>
        </EntityType>
        <EntityType Name="Drivers">
          <Key>
            <PropertyRef Name="Id"/>
          </Key>
          <Property Name="Id" Type="int" StoreGeneratedPattern="Identity" Nullable="false"/>
          <Property Name="Name" Type="nvarchar(max)" Nullable="false"/>
        </EntityType>
        <EntityType Name="CarDriver">
          <Key>
            <PropertyRef Name="Cars_Id"/>
            <PropertyRef Name="Drivers_Id"/>
          </Key>
          <Property Name="Cars_Id" Type="int" Nullable="false"/>
          <Property Name="Drivers_Id" Type="int" Nullable="false"/>
        </EntityType>
        <Association Name="FK_CarDriver_Car">
          <End Role="Car" Type="Ef2PlaygroundModel_3.Store.Cars" Multiplicity="1"/>
          <End Role="CarDriver" Type="Ef2PlaygroundModel_3.Store.CarDriver" Multiplicity="*"/>
          <ReferentialConstraint>
            <Principal Role="Car">
              <PropertyRef Name="Id"/>
            </Principal>
            <Dependent Role="CarDriver">
              <PropertyRef Name="Cars_Id"/>
            </Dependent>
          </ReferentialConstraint>
        </Association>
        <Association Name="FK_CarDriver_Driver">
          <End Role="CarDriver" Type="Ef2PlaygroundModel_3.Store.CarDriver" Multiplicity="*"/>
          <End Role="Driver" Type="Ef2PlaygroundModel_3.Store.Drivers" Multiplicity="1"/>
          <ReferentialConstraint>
            <Principal Role="Driver">
              <PropertyRef Name="Id"/>
            </Principal>
            <Dependent Role="CarDriver">
              <PropertyRef Name="Drivers_Id"/>
            </Dependent>
          </ReferentialConstraint>
        </Association>
      </Schema>
    </edmx:StorageModels>
    <!-- CSDL content -->
    <edmx:ConceptualModels>
      <Schema xmlns="http://schemas.microsoft.com/ado/2008/09/edm" xmlns:cg="http://schemas.microsoft.com/ado/2006/04/codegeneration" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" Namespace="Ef2PlaygroundModel_3" Alias="Self" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation">
        <EntityContainer Name="Ef2PlaygroundModel_3Container" annotation:LazyLoadingEnabled="true">
          <EntitySet Name="Cars" EntityType="Ef2PlaygroundModel_3.Car"/>
          <EntitySet Name="Drivers" EntityType="Ef2PlaygroundModel_3.Driver"/>
          <AssociationSet Name="CarDriver" Association="Ef2PlaygroundModel_3.CarDriver">
            <End Role="Car" EntitySet="Cars"/>
            <End Role="Driver" EntitySet="Drivers"/>
          </AssociationSet>
        </EntityContainer>
        <EntityType Name="Car">
          <Key>
            <PropertyRef Name="Id"/>
          </Key>
          <Property Type="Int32" Name="Id" Nullable="false" annotation:StoreGeneratedPattern="Identity"/>
          <Property Type="String" Name="Brand" Nullable="false"/>
          <Property Type="String" Name="Model" Nullable="false"/>
          <Property Type="DateTime" Name="ReleaseDate" Nullable="true"/>
          <NavigationProperty Name="Drivers" Relationship="Ef2PlaygroundModel_3.CarDriver" FromRole="Car" ToRole="Driver"/>
        </EntityType>
        <EntityType Name="Driver">
          <Key>
            <PropertyRef Name="Id"/>
          </Key>
          <Property Type="Int32" Name="Id" Nullable="false" annotation:StoreGeneratedPattern="Identity"/>
          <Property Type="String" Name="Name" Nullable="false"/>
          <NavigationProperty Name="Cars" Relationship="Ef2PlaygroundModel_3.CarDriver" FromRole="Driver" ToRole="Car"/>
        </EntityType>
        <Association Name="CarDriver">
          <End Type="Ef2PlaygroundModel_3.Car" Role="Car" Multiplicity="*"/>
          <End Type="Ef2PlaygroundModel_3.Driver" Role="Driver" Multiplicity="*"/>
        </Association>
      </Schema>
    </edmx:ConceptualModels>
    <!-- C-S mapping content -->
    <edmx:Mappings>
      <Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2008/09/mapping/cs">
        <EntityContainerMapping StorageEntityContainer="Ef2PlaygroundModel_3StoreContainer" CdmEntityContainer="Ef2PlaygroundModel_3Container">
          <EntitySetMapping Name="Cars">
            <EntityTypeMapping TypeName="IsTypeOf(Ef2PlaygroundModel_3.Car)">
              <MappingFragment StoreEntitySet="Cars">
                <ScalarProperty Name="Id" ColumnName="Id"/>
                <ScalarProperty Name="Brand" ColumnName="Brand"/>
                <ScalarProperty Name="Model" ColumnName="Model"/>
                <ScalarProperty Name="ReleaseDate" ColumnName="ReleaseDate"/>
              </MappingFragment>
            </EntityTypeMapping>
          </EntitySetMapping>
          <EntitySetMapping Name="Drivers">
            <EntityTypeMapping TypeName="IsTypeOf(Ef2PlaygroundModel_3.Driver)">
              <MappingFragment StoreEntitySet="Drivers">
                <ScalarProperty Name="Id" ColumnName="Id"/>
                <ScalarProperty Name="Name" ColumnName="Name"/>
              </MappingFragment>
            </EntityTypeMapping>
          </EntitySetMapping>
          <AssociationSetMapping Name="CarDriver" TypeName="Ef2PlaygroundModel_3.CarDriver" StoreEntitySet="CarDriver">
            <EndProperty Name="Car">
              <ScalarProperty Name="Id" ColumnName="Cars_Id"/>
            </EndProperty>
            <EndProperty Name="Driver">
              <ScalarProperty Name="Id" ColumnName="Drivers_Id"/>
            </EndProperty>
          </AssociationSetMapping>
        </EntityContainerMapping>
      </Mapping>
    </edmx:Mappings>
  </edmx:Runtime>
  <!-- EF Designer content (DO NOT EDIT MANUALLY BELOW HERE) -->
  <edmx:Designer xmlns="http://schemas.microsoft.com/ado/2008/10/edmx">
    <edmx:Connection>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="MetadataArtifactProcessing" Value="EmbedInOutputAssembly"/>
      </DesignerInfoPropertySet>
    </edmx:Connection>
    <edmx:Options>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="ValidateOnBuild" Value="true"/>
        <DesignerProperty Name="EnablePluralization" Value="False"/>
        <DesignerProperty Name="CodeGenerationStrategy" Value="None"/>
      </DesignerInfoPropertySet>
    </edmx:Options>
    <!-- Diagram content (shape and connector positions) -->
    <edmx:Diagrams>
      <Diagram Name="Ef2PlaygroundModel_3">
        <EntityTypeShape EntityType="Ef2PlaygroundModel_3.Car" Width="1.5" PointX="3.25" PointY="1.625" Height="1.787985026041667"/>
        <EntityTypeShape EntityType="Ef2PlaygroundModel_3.Driver" Width="1.5" PointX="5.375" PointY="1.625" Height="1.59568359375"/>
        <AssociationConnector Association="Ef2PlaygroundModel_3.CarDriver">
          <ConnectorPoint PointX="4.75" PointY="2.422841796875"/>
          <ConnectorPoint PointX="5.375" PointY="2.422841796875"/>
        </AssociationConnector>
      </Diagram>
    </edmx:Diagrams>
  </edmx:Designer>
</edmx:Edmx>

应用程序配置：

<configuration>
  <connectionStrings>
    <add 
      name="Ef2PlaygroundModel_3Container" 
      connectionString="metadata=res://*/Ef2PlaygroundModel_3.csdl|res://*/Ef2PlaygroundModel_3.ssdl|res://*/Ef2PlaygroundModel_3.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=.\SqlExpress;Initial Catalog=Ef2PlaygroundModel_3;Integrated Security=True;MultipleActiveResultSets=True&quot;" 
      providerName="System.Data.EntityClient" 
    />
  </connectionStrings>
</configuration>

Ef2PlaygroundModel_3Pocos.cs：

using System;
using System.Collections.Generic;
using System.Data.Objects;

namespace EF2_Playground
{
  public class Car
  {
    public Car()
    {
      Drivers = new List<Driver>();
    }

    public int Id { get; set; }
    public string Brand { get; set; }
    public string Model { get; set; }
    public DateTime? ReleaseDate { get; set; }

    public virtual List<Driver> Drivers { get; private set; }
  }

  public class Driver
  {
    public Driver()
    {
      Cars = new List<Car>();
    }

    public int Id { get; set; }
    public string Name { get; set; }

    public virtual List<Car> Cars { get; private set; }
  }

  public class Ef2PlaygroundModel_3Container : ObjectContext
  { 
    public Ef2PlaygroundModel_3Container()
      : base("name=Ef2PlaygroundModel_3Container") 
    {
      ContextOptions.LazyLoadingEnabled = true;
    }

    public IObjectSet<Car> Cars
    {
      get { return CreateObjectSet<Car>(); }
    }

    public IObjectSet<Driver> Drivers
    {
      get { return CreateObjectSet<Driver>(); }
    }
  }
}

程序.cs：

using System;

namespace EF2_Playground
{
  class Program
  {
    static void Main(string[] args)
    {
      using (var ctx = new Ef2PlaygroundModel_3Container())
      {
        foreach (var driver in ctx.Drivers)
        {
          Console.WriteLine(driver.Name);
          foreach (var car in driver.Cars)
          {
            Console.WriteLine("   drives a {0} - {1} (released on {2})", car.Brand, car.Model, car.ReleaseDate);
          }
        }
      }
    }
  }
}

最后，当我将 Model1.edmx 添加到项目中时，它就破坏了整个事情：

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="2.0" xmlns:edmx="http://schemas.microsoft.com/ado/2008/10/edmx">
  <!-- EF Runtime content -->
  <edmx:Runtime>
    <!-- SSDL content -->
    <edmx:StorageModels>
      <Schema xmlns="http://schemas.microsoft.com/ado/2009/02/edm/ssdl" Namespace="Model1.Store" Alias="Self" Provider="System.Data.SqlClient" ProviderManifestToken="2005">
        <EntityContainer Name="Model1TargetContainer">
        </EntityContainer>
      </Schema>
    </edmx:StorageModels>
    <!-- CSDL content -->
    <edmx:ConceptualModels>
      <Schema xmlns="http://schemas.microsoft.com/ado/2008/09/edm" xmlns:cg="http://schemas.microsoft.com/ado/2006/04/codegeneration" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" Namespace="Model1" Alias="Self" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation">
        <EntityContainer Name="Model1Container" annotation:LazyLoadingEnabled="true">
        </EntityContainer>
      </Schema>
    </edmx:ConceptualModels>
    <!-- C-S mapping content -->
    <edmx:Mappings>
      <Mapping xmlns="http://schemas.microsoft.com/ado/2008/09/mapping/cs" Space="C-S">
        <Alias Key="Model" Value="Model1"/>
        <Alias Key="Target" Value="Model1.Store"/>
        <EntityContainerMapping CdmEntityContainer="Model1Container" StorageEntityContainer="Model1TargetContainer">
        </EntityContainerMapping>
      </Mapping>
    </edmx:Mappings>
  </edmx:Runtime>
  <!-- EF Designer content (DO NOT EDIT MANUALLY BELOW HERE) -->
  <edmx:Designer xmlns="http://schemas.microsoft.com/ado/2008/10/edmx">
    <edmx:Connection>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="MetadataArtifactProcessing" Value="EmbedInOutputAssembly"/>
      </DesignerInfoPropertySet>
    </edmx:Connection>
    <edmx:Options>
      <DesignerInfoPropertySet>
        <DesignerProperty Name="ValidateOnBuild" Value="true"/>
        <DesignerProperty Name="EnablePluralization" Value="False"/>
      </DesignerInfoPropertySet>
    </edmx:Options>
    <!-- Diagram content (shape and connector positions) -->
    <edmx:Diagrams>
      <Diagram Name="Model1"/>
    </edmx:Diagrams>
  </edmx:Designer>
</edmx:Edmx>
entity-framework .net-4.0 entity-framework-4
3个回答
21
投票

好吧，我想我已经明白了。我将第二个模型（破坏项目的模型）简化为以下内容：

Class1.cs

using System.Data.Objects.DataClasses;
[assembly: EdmSchemaAttribute()]

砰！出现了众所周知的异常。

在很多情况下，阅读文档会有所帮助：

如果将任何映射属性应用于自定义数据类（包括程序集级别的 EdmSchemaAttribute），则不支持映射 POCO 实体。

当然，我实际上并没有将映射属性添加到自定义数据类，但这对于 EdmSchemaAttribute 来说并不重要，因为它存在于程序集级别。

添加第二个非 POCO 模型会导致代码生成，从而产生包含（至少）EdmSchemaAttribute 且不受支持的类。

我学到了什么：不要在一个组件中混合 POCO 和非 POCO 模型。

0
投票

我的猜测是 ef 正在寻找错误的模型。这些模型是否有可能使用相同的命名空间？您可以在属性窗口中修改 CSDL 命名空间。如果修改新的空模型的 csdl 命名空间会发生什么？

0
投票

在 *.edmx 的属性中，如果您使用 POCO，则应将 CodeGenerationStrategy 设置为 none。

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