由于创建上下文实例后立即引发异常，因此全新的项目和 Entity Framework 将无法启动。
Entity Framework 引发以下异常:
引用:
通过nuget软件包管理器:
Install-Package entityframework
非常简单的上下文和实体:
public class TextDbContext : DbContext
{
public TextDbContext()
: base("Test")
{
}
public DbSet<TestEntity> TestEntity { get; set; }
}
public class TestEntity
{
public int Id { get; set; }
public string Name { get; set; }
}
static void Main(string[] args)
{
var test = ConfigurationManager.ConnectionStrings["Test"].ConnectionString;
using (var conn = new SqlConnection(test))
{
conn.Open();
var cmd = new SqlCommand("Select * from testtable", conn);
var result = cmd.ExecuteReader();
}
//exception thrown on this line is the same as the one in the context
var instance = SqlProviderServices.Instance;
using (var db = new TextDbContext())
{
var item = new TestEntity
{
Name = "xyz"
};
db.TestEntity.Add(item);
db.SaveChanges();
}
}
这是当前的app.config文件:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<connectionStrings>
<add name="Test" connectionString="server=localhost;database=Test;Data Source=localhost;Integrated Security=True;Pooling=True" providerName="System.Data.SqlClient" />
</connectionStrings>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
</configuration>
堆栈跟踪如下:
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, BindingFlags invokeAttr, Binder binder, Object[] index, CultureInfo culture)
at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
at System.Data.Entity.Utilities.MemberInfoExtensions.GetValue(MemberInfo memberInfo)
at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(Type providerType)
at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName)
at System.Data.Entity.Internal.AppConfig.<.ctor>b__2(ProviderElement e)
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at System.Data.Entity.Internal.AppConfig.<.ctor>b__1()
at System.Lazy`1.CreateValue()
at System.Lazy`1.LazyInitValue()
at System.Lazy`1.get_Value()
at System.Data.Entity.Internal.AppConfig.get_DbProviderServices()
at System.Data.Entity.Infrastructure.DependencyResolution.AppConfigDependencyResolver.RegisterDbProviderServices()
at System.Data.Entity.Infrastructure.DependencyResolution.AppConfigDependencyResolver.GetServiceFactory(Type type, String name)
at System.Data.Entity.Infrastructure.DependencyResolution.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.Infrastructure.DependencyResolution.AppConfigDependencyResolver.GetService(Type type, Object key)
at System.Data.Entity.Infrastructure.DependencyResolution.DbDependencyResolverExtensions.GetServiceAsServices(IDbDependencyResolver resolver, Type type, Object key)
at System.Data.Entity.Infrastructure.DependencyResolution.AppConfigDependencyResolver.GetServices(Type type, Object key)
at System.Data.Entity.Infrastructure.DependencyResolution.ResolverChain.<>c__DisplayClass6.<GetServices>b__5(IDbDependencyResolver r)
at System.Linq.Enumerable.<SelectManyIterator>d__14`2.MoveNext()
at System.Linq.Enumerable.<ConcatIterator>d__71`1.MoveNext()
at System.Linq.Enumerable.<OfTypeIterator>d__aa`1.MoveNext()
at System.Data.Entity.Utilities.IEnumerableExtensions.Each[T](IEnumerable`1 ts, Action`1 action)
at System.Data.Entity.Infrastructure.DependencyResolution.InternalConfiguration.Lock()
at System.Data.Entity.Infrastructure.DependencyResolution.DbConfigurationManager.<.ctor>b__1()
at System.Lazy`1.CreateValue()
at System.Lazy`1.LazyInitValue()
at System.Lazy`1.get_Value()
at System.Data.Entity.Infrastructure.DependencyResolution.DbConfigurationManager.GetConfiguration()
at System.Data.Entity.DbContext.InitializeLazyInternalContext(IInternalConnection internalConnection, DbCompiledModel model)
at System.Data.Entity.DbContext..ctor(String nameOrConnectionString)
at test2.TextDbContext..ctor() in \\srv\users\carl.tierney\Documents\Visual Studio 2013\Projects\test2\test2\test2context.cs:line 13
at test2.Program.Main(String[] args) in \\srv\users\carl.tierney\Documents\Visual Studio 2013\Projects\test2\test2\Program.cs:line 13
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
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()
最佳答案
如果您像我一样发现Gac中未安装EF，那么下一步是在记下软件包的版本后将其卸载。我使用NuGet，所以我去了Tools ... Library Package Manager ... Package Manager Console。我首先尝试了GUI，但卸载失败，截至撰写本文时，您只能安装软件包的最新版本。
关于c# - 为什么 Entity Framework 6.1.3抛出 “Could not load type ' System.Data.Entity.Infrastructure.TableExistenceChecker'”，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29051931/