試圖在PostgreSQL中使用EF 6 - 無法找到或加載已註冊的.Net Framework數據提供程序

Question

我想使用EF 6 Code First與Npgsql提供程序。當我嘗試在包管理器運行Add-遷移命令我有以下異常：Failed to find or load the registered .Net Framework Data Provider.

PM> Add-Migration -Force -ConfigurationTypeName "TestDbContextMigration" -ConnectionString "Server=localhost;Port=5432;Database=test_db;User Id=test;Password=konnaya;" -ConnectionProviderName "Npgsql" 
cmdlet Add-Migration at command pipeline position 1 
Supply values for the following parameters: 
Name: 123 
System.Configuration.ConfigurationErrorsException: Failed to find or load the registered .Net Framework Data Provider. 
    at System.Data.Common.DbProviderFactories.GetFactory(DataRow providerRow) 
    at System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName) 
    at System.Data.Entity.Infrastructure.DependencyResolution.DefaultProviderFactoryResolver.GetService(Type type, Object key, Func`3 handleFailedLookup) 
    at System.Data.Entity.Infrastructure.DependencyResolution.DefaultProviderFactoryResolver.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.CachingDependencyResolver.<>c__DisplayClass1.<GetService>b__0(Tuple`2 k) 
    at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory) 
    at System.Data.Entity.Infrastructure.DependencyResolution.CachingDependencyResolver.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.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.Infrastructure.DependencyResolution.ResolverChain.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.RootDependencyResolver.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.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.Infrastructure.DependencyResolution.ResolverChain.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.CompositeResolver`2.GetService(Type type, Object key) 
    at System.Data.Entity.Infrastructure.DependencyResolution.DbDependencyResolverExtensions.GetService[T](IDbDependencyResolver resolver, Object key) 
    at System.Data.Entity.Internal.LazyInternalConnection.CreateConnectionFromProviderName(String providerInvariantName) 
    at System.Data.Entity.Internal.LazyInternalConnection.InitializeFromConnectionStringSetting(ConnectionStringSettings appConfigConnection) 
    at System.Data.Entity.Internal.LazyInternalConnection.Initialize() 
    at System.Data.Entity.Internal.LazyInternalConnection.get_Connection() 
    at System.Data.Entity.Internal.LazyInternalContext.get_Connection() 
    at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbProviderInfo modelProviderInfo, AppConfig config, DbConnectionInfo connectionInfo, Func`1 resolver) 
    at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext, DatabaseExistenceState existenceState, Boolean calledByCreateDatabase) 
    at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration) 
    at System.Data.Entity.Migrations.Design.MigrationScaffolder..ctor(DbMigrationsConfiguration migrationsConfiguration) 
    at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldRunner.Run() 
    at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) 
    at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate) 
    at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner) 
    at System.Data.Entity.Migrations.Design.ToolingFacade.Scaffold(String migrationName, String language, String rootNamespace, Boolean ignoreChanges) 
    at System.Data.Entity.Migrations.AddMigrationCommand.Execute(String name, Boolean force, Boolean ignoreChanges) 
    at System.Data.Entity.Migrations.AddMigrationCommand.<>c__DisplayClass2.<.ctor>b__0() 
    at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command) 
Failed to find or load the registered .Net Framework Data Provider. 

的Update-Database命令給出了相同的結果。

來源https://github.com/DonTomato/PgEF

這是一個簡單的例子，不包含任何多餘了這個話題。

Answer 1

你需要有添加到GAC以及在應用程序的配置文件中添加以下配置的Npgsql.dll，Mono.Security.dll和Npgsql.EntityFramework.dll組件

<system.data> 
    <DbProviderFactories> 
    <remove invariant="Npgsql" /> 
    <add name="Npgsql Data Provider" invariant="Npgsql" support="FF" description=".Net Framework Data Provider for Postgresql" type="Npgsql.NpgsqlFactory, Npgsql" /> 
    </DbProviderFactories> 
</system.data> 
<entityFramework> 
    <defaultConnectionFactory type="Npgsql.NpgsqlConnectionFactory, Npgsql" /> 
    <providers> 
    <provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, Npgsql.EntityFramework" /> 
    </providers> 
</entityFramework>