Question

我正在编写一个与EF和MySql一起使用的桌面应用程序。 EF创建的每种类型都映射到本地类型。使用Visual Studio提供的单元测试框架测试包装器方法时，所有测试运行 - 我看到进出数据库的信息。但是，当我从我为集成测试添加的临时控制台程序运行相同的代码时，EF会引发以下异常：

System.NullReferenceException: Object reference not set to an instance of an object.
   at MySql.Data.MySqlClient.MySqlClientFactory.get_MySqlDbProviderServicesInstance()
   at MySql.Data.MySqlClient.MySqlClientFactory.System.IServiceProvider.GetService(Type serviceType)
   at System.Data.Common.DbProviderServices.GetProviderServices(DbProviderFactory factory)
   at System.Data.Metadata.Edm.StoreItemCollection.Loader.InitializeProviderManifest(Action`3 addError)
   at System.Data.Metadata.Edm.StoreItemCollection.Loader.OnProviderManifestTokenNotification(String token, Action`3 addError)
   at System.Data.EntityModel.SchemaObjectModel.Schema.HandleProviderManifestTokenAttribute(XmlReader reader)
   at System.Data.EntityModel.SchemaObjectModel.Schema.HandleAttribute(XmlReader reader)
   at System.Data.EntityModel.SchemaObjectModel.SchemaElement.ParseAttribute(XmlReader reader)
   at System.Data.EntityModel.SchemaObjectModel.SchemaElement.Parse(XmlReader reader)
   at System.Data.EntityModel.SchemaObjectModel.Schema.HandleTopLevelSchemaElement(XmlReader reader)
   at System.Data.EntityModel.SchemaObjectModel.Schema.InternalParse(XmlReader sourceReader, String sourceLocation)
   at System.Data.EntityModel.SchemaObjectModel.Schema.Parse(XmlReader sourceReader, String sourceLocation)
   at System.Data.EntityModel.SchemaObjectModel.SchemaManager.ParseAndValidate(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths, SchemaDataModelOption dataModel, AttributeValueNotification providerNotification, AttributeValueNotification providerManifestTokenNotification, ProviderManifestNeed
ed providerManifestNeeded, IList`1& schemaCollection)
   at System.Data.Metadata.Edm.StoreItemCollection.Loader.LoadItems(IEnumerable`1 xmlReaders, IEnumerable`1 sourceFilePaths)
   at System.Data.Metadata.Edm.StoreItemCollection.Init(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths, Boolean throwOnError, DbProviderManifest& providerManifest, DbProviderFactory& providerFactory, String& providerManifestToken, Memoizer`2& cachedCTypeFunction)
   at System.Data.Metadata.Edm.StoreItemCollection..ctor(IEnumerable`1 xmlReaders, IEnumerable`1 filePaths)
   at System.Data.Metadata.Edm.MetadataCache.StoreMetadataEntry.LoadStoreCollection(EdmItemCollection edmItemCollection, MetadataArtifactLoader loader)
   at System.Data.Metadata.Edm.MetadataCache.StoreItemCollectionLoader.LoadItemCollection(StoreMetadataEntry entry)
   at System.Data.Metadata.Edm.MetadataCache.LoadItemCollection[T](IItemCollectionLoader`1 itemCollectionLoader, T entry)
   at System.Data.Metadata.Edm.MetadataCache.GetOrCreateStoreAndMappingItemCollections(String cacheKey, MetadataArtifactLoader loader, EdmItemCollection edmItemCollection, Object& entryToken)
   at System.Data.EntityClient.EntityConnection.LoadStoreItemCollections(MetadataWorkspace workspace, DbConnection storeConnection, DbProviderFactory factory, DbConnectionOptions connectionOptions, EdmItemCollection edmItemCollection, MetadataArtifactLoader artifactLoader)
   at System.Data.EntityClient.EntityConnection.GetMetadataWorkspace(Boolean initializeAllCollections)
   at System.Data.EntityClient.EntityConnection.InitializeMetadata(DbConnection newConnection, DbConnection originalConnection, Boolean closeOriginalConnectionOnFailure)
   at System.Data.EntityClient.EntityConnection.Open()
   at System.Data.Objects.ObjectContext.EnsureConnection()
   at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
   at System.Data.Objects.ObjectContext.SaveChanges()
   at DataAccess.PhoneTypeAccess.AddNewPhoneType(PhoneType newPhoneType) in C:\Users\Mordechai\Desktop\Progaming\GitHub\VirtualGabbai\VirtGabbai\DataAccess\PhoneTypeAccess.cs:line 66
   at TempUI.Program.Main(String[] args) in C:\Users\Mordechai\Desktop\Progaming\GitHub\VirtualGabbai\VirtGabbai\TempUI\Program.cs:line 17

这是我在program.cs中运行的代码

static void Main(string[] args)
        {
            try
            {
                PhoneTypeAccess.AddNewPhoneType(new PhoneType(1, "phone"));
                var blah = PhoneTypeAccess.GetPhoneTypeById(1);
                Console.WriteLine(blah.ToString());
                //Cache.CacheData.t_phone_types.AddObject(t_phone_types.Createt_phone_types(1, "some Type"));
                //var thingOne = t_people.Createt_people(1);
                //Cache.CacheData.t_people.AddObject(thingOne);
                //Cache.CacheData.SaveChanges();
                //PhoneNumberAccess.AddNewPhoneNumber(new PhoneNumber(1, "some number", new PhoneType(1, "some type")));
                //var test = PhoneNumberAccess.GetPhoneNumberById(1);
                //Console.WriteLine(test.ToString
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }

测试包含以下代码

[TestMethod()]
    public void AddNewPhoneTypeTest()
    {
        PhoneType newPhoneType = new PhoneType(21, "phonetype:21");
        PhoneTypeAccess.AddNewPhoneType(newPhoneType);
        PhoneType actual = PhoneTypeAccess.GetPhoneTypeById(21);
        Assert.IsTrue(newPhoneType.Equals(actual));
    }

被调用的代码如下

 public static void AddNewPhoneType(PhoneType newPhoneType)
    {
        t_phone_types phoneTypeToAdd = PhoneTypeAccess.ConvertSingleLocalPhoneTypeToDbType(newPhoneType);
        Cache.CacheData.t_phone_types.AddObject(phoneTypeToAdd);
        Cache.CacheData.SaveChanges();
    }

当我在Cache.CacheData.SaveChanges()行进行调试时，我会看到以下代码

/// <summary>
/// Allows access to the cached data - but only a single (and constant) instance of it
///  -[the code can create another one but it will be a completly different set of data]-
/// </summary>
public static class Cache
{
    // Data members
    private static zera_leviEntities m_dsDataSet = new zera_leviEntities();

    /// <summary>
    /// Allows outside access to the main data set
    ///  - without letting the user access it any other way
    /// </summary>
    public static zera_leviEntities CacheData
    {
        get
        {
            return m_dsDataSet;
        }
    }
}

我唯一可以看到的事实是，在实体集中确实没有对象。但没有迹象表明原因我看了一遍，没找到任何帮助。我被困住直到我开始运行所以我希望有人可以帮助我谢谢

编辑：在转换方法中添加

private static t_phone_types ConvertSingleLocalPhoneTypeToDbType(PhoneType localTypePhoneType)
    {
        return t_phone_types.Createt_phone_types(localTypePhoneType._Id, localTypePhoneType.PhoneTypeName);
    }

t_phone_types.Createt_phone_types（）方法是EF的一部分

编辑：我现在也通过将整个解决方案中的引用更改为MySql Adapter的更新版本来设法打破测试现在测试也抛出相同的异常。另外，在构建时我收到以下错误：

Error 4: Could not load file or assembly 'MySql.Data, Version=6.7.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) C:\Users\Mordechai\Desktop\Progaming\GitHub\VirtualGabbai\VirtGabbai\Data\EntityCache.edmx

但它仍然会运行（只是抛出异常）

Answer 1

嗯....我经过多次试验和错误后设法找出了问题。 MySQl适配器分为两部分。一个用于所有连接，另一个用于与EF特别连接。现在我添加了第二个dll，它运行正常。

实体框架不保存生产环境的变化

1 个答案: