我正在使用實體框架6 alpha3創建使用.NET4.5的Web應用程序,該實用程序使用新的SQL Compact數據庫。該數據庫尚不存在。錯誤「無法設置類型爲MyNamespace.MyCustomInitializer,MyAssembly的數據庫初始值設定項」無法加載MyContext類型
我有一個Web表單下面的代碼:
public IQueryable<Job> listJobs_GetData()
{
var db = new JournalistContext();
IQueryable<Job> query = db.Jobs.Where(d => d.JobStart > DateTime.Now)
.OrderBy(s => s.JobStart)
.Take(10);
return query;
}
其中JournalistContext從派生的DbContext。 它創建JournalistContext的實例ok,但是當執行下一行時,它會拋出下面的異常。 我猜數據庫不存在,它試圖調用初始化程序,但是失敗。
System.InvalidOperationException was unhandled by user code
HResult=-2146233079
Message=Failed to set database initializer of type 'TSJ.Models.MyCustomInitializer, TSJ' for DbContext type 'TSJ.JournalistContext, TSJ' specified in the application configuration. See inner exception for details.
Source=EntityFramework
StackTrace:
at System.Data.Entity.Internal.InitializerConfig.TryGetInitializer(Type requiredContextType, String contextTypeName, String initializerTypeName, Boolean isDisabled, Func`1 initializerArgs, Func`3 exceptionMessage)
at System.Data.Entity.Internal.InitializerConfig.<>c__DisplayClass6.<TryGetInitializerFromEntityFrameworkSection>b__1(ContextElement e)
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.Internal.InitializerConfig.TryGetInitializerFromEntityFrameworkSection(Type contextType)
at System.Data.Entity.Internal.InitializerConfig.TryGetInitializer(Type contextType)
at System.Data.Entity.Config.AppConfigDependencyResolver.GetServiceFactory(Type type, String name)
at System.Data.Entity.Config.AppConfigDependencyResolver.<>c__DisplayClass1.<GetService>b__0(Tuple`2 t)
at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
at System.Data.Entity.Config.AppConfigDependencyResolver.GetService(Type type, Object key)
at System.Data.Entity.Config.ResolverChain.<>c__DisplayClass3.<GetService>b__0(IDbDependencyResolver r)
at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.Config.ResolverChain.GetService(Type type, Object key)
at System.Data.Entity.Config.CompositeResolver`2.GetService(Type type, Object key)
at System.Data.Entity.Config.IDbDependencyResolverExtensions.GetService(IDbDependencyResolver resolver, Type type)
at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()
at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c)
at System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()
at System.Data.Entity.Internal.InternalContext.Initialize()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.Where[TSource](IQueryable`1 source, Expression`1 predicate)
at TSJ.MainOverview.listJobs_GetData() in ....\Visual Studio 2012\Projects\TSJ\TSJ\MainOverview.aspx.cs:line 27
InnerException: System.TypeLoadException
HResult=-2146233054
Message=Could not load type 'TSJ.JournalistContext' from assembly 'TSJ'.
Source=mscorlib
TypeName=TSJ.JournalistContext
StackTrace:
at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type)
at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName)
at System.RuntimeType.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark)
at System.Type.GetType(String typeName, Boolean throwOnError)
at System.Data.Entity.Internal.InitializerConfig.TryGetInitializer(Type requiredContextType, String contextTypeName, String initializerTypeName, Boolean isDisabled, Func`1 initializerArgs, Func`3 exceptionMessage)
如這裏所描述http://msdn.microsoft.com/en-us/data/jj556606我創建了一個自定義數據庫初始化,它目前是一個空白類:
internal sealed class MyCustomInitializer : MigrateDatabaseToLatestVersion<JournalistContext, TSJ.Migrations.Configuration>
{
}
public class JournalistContext : DbContext
{
public JournalistContext() : base("TSJ")
{
}
...
我的web.config文件中引用這個初始化如下:
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlCeConnectionFactory, EntityFramework">
<parameters>
<parameter value="System.Data.SqlServerCe.4.0" />
</parameters>
</defaultConnectionFactory>
<contexts>
<context type="TSJ.JournalistContext, TSJ">
<databaseInitializer type="TSJ.Models.MyCustomInitializer, TSJ" />
</context>
</contexts>
<providers>
<provider invariantName="System.Data.SqlServerCe.4.0" type="System.Data.Entity.SqlServerCompact.SqlCeProviderServices, EntityFramework.SqlServerCompact, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
</providers>
</entityFramework>
我很難過!有任何想法嗎?
我注意到的另一件事:這些行已經出現在我的web.config文件中。我不確定他們是如何添加的,或者爲什麼。
<system.data>
<DbProviderFactories>
<remove invariant="System.Data.SqlServerCe.4.0" />
<add name="Microsoft SQL Server Compact Data Provider 4.0" invariant="System.Data.SqlServerCe.4.0" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=4.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
</DbProviderFactories>
</system.data>
非常感謝,馬克。
我沒有太多的工作與EF 6 - 但現在看來,這是無法找到你的類型 - 或裝配等 - 嘗試從配置去除「背景」 - 手動加載初始化 - 即數據庫。 SetInitializer。 – NSGaga 2013-04-11 19:35:14
好主意,我把行 'System.Data.Entity.Database.SetInitializer(new System.Data.Entity.MigrateDatabaseToLatestVersion());我的Application_Start方法中的' ,似乎得到它的工作。我不知道爲什麼它沒有在配置文件中工作。 –
2013-04-11 23:05:54
測試,檢查您如何定義,「完全限定名稱」是什麼 - 例如嘗試通過反射從代碼中構建TSJ.JournalistContext(這就是config/EF所看到的)。這應該會引起你的問題。我可以提出一些答案 - 但我們需要更多:) – NSGaga 2013-04-11 23:22:43