如何使用 Mono 设置实体框架/SQL Server

Question

我正在尝试设置一个非常简单的测试项目来评估 Mono Entity Framework 的功能。尝试访问数据时，我在使用 .NET Runtime 时遇到关于解析模型数据的运行时异常。使用 Mono 运行时时，会引发 stackoverflow 异常。

这似乎是编译 CSDL 架构版本 3 时出现的内部单声道错误 - 请参阅 Mono Bugtracker。

所以我的问题是：

如何使用实体框架设置 Mono 以使用 Microsoft SQL Server？由于我找不到太多信息，这是否可能？有没有人使用 EF 成功设置单声道解决方案并遇到类似错误？

这是我到目前为止所做的：

• 已安装 Mono 3.0.1 Beta（最新稳定版不包括 EntityFramework.dll）
• 为 Visual Studio 设置 Mono Profile
• Disabled strong name verification for delay signed assembilies 为 EntityFramework.dll / EntityFramework.SQLServer.dll 并将它们添加到 GAC 以防止运行时错误
• 创建了一个简单的模型 + 添加了代码生成项
• 使用模型编写代码

该代码适用于 Microsoft EntityFramework.dll（版本 6，预发布）。使用 Mono 等效项时，解析实体模型时似乎存在问题：

异常消息（.NET 运行时）：

对象引用未设置为对象的实例。

堆栈跟踪（.NET 运行时）：

   at System.Xml.XmlTextReaderImpl.InitStreamInput(Uri baseUri, String baseUriStr, Stream stream, Byte[] bytes, Int32 byteCount, Encoding encoding)
   at System.Xml.XmlTextReaderImpl..ctor(String url, Stream input, XmlNameTable nt)
   at System.Xml.XmlTextReader..ctor(Stream input)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.Schema.SomSchemaSetHelper.AddXmlSchemaToSet(XmlSchemaSet schemaSet, XmlSchemaResource schemaResource, HashSet`1 schemasAlreadyAdded)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.Schema.SomSchemaSetHelper.AddXmlSchemaToSet(XmlSchemaSet schemaSet, XmlSchemaResource schemaResource, HashSet`1 schemasAlreadyAdded)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.Schema.SomSchemaSetHelper.ComputeSchemaSet(SchemaDataModelOption dataModel)
   at System.Data.Entity.Core.Common.Utils.Memoizer`2.Result.GetValue()
   at System.Data.Entity.Core.Common.Utils.Memoizer`2.Evaluate(TArg arg)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.Schema.SomSchemaSetHelper.GetSchemaSet(SchemaDataModelOption dataModel)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.Schema.Parse(XmlReader sourceReader, String sourceLocation)
   at System.Data.Entity.Core.EntityModel.SchemaObjectModel.SchemaManager.ParseAndValidate(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths, SchemaDataModelOption dataModel, AttributeValueNotification providerNotification, AttributeValueNotification providerManifestTokenNotification, ProviderManifestNeeded providerManifestNeeded, IList`1& schemaCollection)
   at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Loader.LoadItems(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths)
   at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection.Init(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths, Boolean throwOnError, DbProviderManifest& providerManifest, DbProviderFactory& providerFactory, String& providerManifestToken, Memoizer`2& cachedCTypeFunction)
   at System.Data.Entity.Core.Metadata.Edm.StoreItemCollection..ctor(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.StoreMetadataEntry.LoadStoreCollection(EdmItemCollection edmItemCollection, MetadataArtifactLoader loader)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.LoadItemCollection[T](IItemCollectionLoader`1 itemCollectionLoader, T entry)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.GetOrCreateStoreAndMappingItemCollections(String cacheKey, MetadataArtifactLoader loader, EdmItemCollection edmItemCollection, Object& entryToken)
   at System.Data.Entity.Core.EntityClient.EntityConnection.LoadStoreItemCollections(MetadataWorkspace workspace, DbConnection storeConnection, DbConnectionOptions connectionOptions, EdmItemCollection edmItemCollection, MetadataArtifactLoader artifactLoader)
   at System.Data.Entity.Core.EntityClient.EntityConnection.GetMetadataWorkspace(Boolean initializeAllCollections)
   at System.Data.Entity.Core.EntityClient.EntityConnection.InitializeMetadata(DbConnection newConnection, DbConnection originalConnection, Boolean closeOriginalConnectionOnFailure)
   at System.Data.Entity.Core.EntityClient.EntityConnection.Open()
   at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection()
   at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<GetEnumerator>m__2C3()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
   at System.Linq.Queryable.Count[TSource](IQueryable`1 source)
   at EntityFrameworkMono.Program.Main(String[] args) in c:\Users\Christopher Dresel\Documents\Visual Studio 2012\Projects\New\EntityFrameworkMono\EntityFrameworkMono\Program.cs:line 17
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart() 

异常消息（单声道运行时）：

请求的操作导致堆栈溢出。

Stacktrace（单声道运行时）：

  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaElement.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaElement.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0 
  at System.Xml.Schema.XmlSchemaGroupBase.CheckRecursion (Int32 depth, System.Xml.Schema.ValidationEventHandler h, System.Xml.Schema.XmlSchema schema) [0x00000] in <filename unknown>:0
...

这是我正在使用的代码：

CustomerEntities entities = new CustomerEntities();
var count = entities.Customers.Count(); // Exception throws here

Console.WriteLine(count);
Console.ReadKey();

EDMX文件

<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="3.0" xmlns:edmx="http://schemas.microsoft.com/ado/2009/11/edmx">
    <!-- EF Runtime content -->
    <edmx:Runtime>
        <!-- SSDL content -->
        <edmx:StorageModels>
            <Schema Namespace="CustomerModel.Store" Alias="Self" Provider="System.Data.SqlClient" ProviderManifestToken="2008" xmlns="http://schemas.microsoft.com/ado/2009/11/edm/ssdl">
                <EntityContainer Name="CustomerModelStoreContainer">
                    <EntitySet Name="Customer" EntityType="CustomerModel.Store.Customer" store:Type="Tables" Schema="dbo" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" />
                </EntityContainer>
                <EntityType Name="Customer">
                    <Key>
                        <PropertyRef Name="CustomerID" />
                    </Key>
                    <Property Name="CustomerID" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
                    <Property Name="CustomerName" Type="nvarchar" Nullable="false" MaxLength="50" />
                </EntityType>
            </Schema>
        </edmx:StorageModels>
        <!-- CSDL content -->
        <edmx:ConceptualModels>
            <Schema Namespace="CustomerModel" Alias="Self" annotation:UseStrongSpatialTypes="false" xmlns="http://schemas.microsoft.com/ado/2009/11/edm" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation">
                <EntityContainer Name="CustomerEntities" annotation:LazyLoadingEnabled="true">
                    <EntitySet Name="Customers" EntityType="CustomerModel.Customer" />
                </EntityContainer>
                <EntityType Name="Customer">
                    <Key>
                        <PropertyRef Name="CustomerID" />
                    </Key>
                    <Property Name="CustomerID" Type="Int32" Nullable="false" annotation:StoreGeneratedPattern="Identity" />
                    <Property Name="CustomerName" Type="String" Nullable="false" MaxLength="50" Unicode="true" FixedLength="false" />
                </EntityType>
            </Schema>
        </edmx:ConceptualModels>
        <!-- C-S mapping content -->
        <edmx:Mappings>
            <Mapping Space="C-S" xmlns="http://schemas.microsoft.com/ado/2009/11/mapping/cs">
                <EntityContainerMapping StorageEntityContainer="CustomerModelStoreContainer" CdmEntityContainer="CustomerEntities">
                    <EntitySetMapping Name="Customers">
                        <EntityTypeMapping TypeName="CustomerModel.Customer">
                            <MappingFragment StoreEntitySet="Customer">
                                <ScalarProperty Name="CustomerID" ColumnName="CustomerID" />
                                <ScalarProperty Name="CustomerName" ColumnName="CustomerName" />
                            </MappingFragment>
                        </EntityTypeMapping>
                    </EntitySetMapping>
                </EntityContainerMapping>
            </Mapping>
        </edmx:Mappings>
    </edmx:Runtime>
</edmx:Edmx>

最后是我使用的连接字符串：

<connectionStrings>
    <add name="CustomerEntities"
         connectionString="metadata=.\CustomerModel.csdl|.\CustomerModel.ssdl|.\CustomerModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=CHRISTOPHERPC\SQLExpress;initial catalog=test;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" 
         providerName="System.Data.EntityClient"/>
</connectionStrings>

Answer 1

Dresel，由于我在这个网站上的声誉可能会产生误导，我可以肯定地说，目前不推荐使用带有 mono 的 EntityFramework 方法。尽管它在技术上受到“支持”，但该库的大部分内容充其量是无法使用的。在花了大约一个月的时间尽可能地挖掘之后，我无法确定将一个功能齐全的网站建立在 %20 以上的可能性。我改为使用 NHibernate，并且对结果感到非常兴奋。并建议在 EF Mono 项目的基础进一步巩固之前也这样做。 Nhibernate Example (using MySQL, MSSQL supported)

我希望这至少会有所帮助，因为这只是我的真诚想法。无论你选择做什么，祝你好运，我知道这个 MS 开源举措可能会变得非常“障碍”