我正在编写一个适用于 EF 和 MySql 的桌面应用程序。EF 创建的每种类型都有一个映射到本地类型。使用 Visual Studio 提供的单元测试框架测试包装器方法时，所有测试都运行 - 我看到进出数据库的信息。但是，当我从为集成测试添加的临时控制台程序中运行相同的代码时，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();
}
当我在线调试时Cache.CacheData.SaveChanges()，我得到以下代码
/// <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;
}
}
}
我唯一能看到的是，在实体集中确实没有对象。但是没有任何迹象表明为什么我四处寻找并没有找到任何有帮助的东西。我被卡住了，直到我运行它，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：我现在也设法通过将整个解决方案中的引用更改为 MySql 适配器的更新版本来打破测试现在测试也抛出相同的异常。此外，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
但是，它仍然会运行（只是它抛出异常）