Entity Framework 6二级缓存，转码为vb.net

Question

当我使用 entity framework 从数据中执行大量导入以放入 sql 时，我的代码必须检查导致对 sql 服务器重复命令的相同外键.我相信我需要使用二级缓存，我尝试使用 efcache from nuget，但由于我只习惯 vb.net，我在转换以下 C# 代码时遇到了问题：

public class Configuration : DbConfiguration
{
  public Configuration()
  {
    var transactionHandler = new CacheTransactionHandler(new InMemoryCache());

    AddInterceptor(transactionHandler);

    Loaded +=
      (sender, args) => args.ReplaceService<DbProviderServices>(
        (s, _) => new CachingProviderServices(s, transactionHandler, 
          new DefaultCachingPolicy()));
  }
}

到vb

Imports System.Data.Entity
Imports EFCache
Public Class Configuration
    Inherits DbConfiguration
    Public Sub New()
        Dim transactionHandler = New CacheTransactionHandler(New InMemoryCache())

        AddInterceptor(transactionHandler)

        AddHandler Loaded, Function(sender, args) args.ReplaceService(Of 
         DbProviderServices)(Function(s, _) New CachingProviderServices(s, 
         transactionHandler, New DefaultCachingPolicy()))
    End Sub
End Class

我知道我需要将 c# += 更改为 addhandler，但它无法识别 dbproviderservices、下划线 _ 和 DefaultCachingPolicy。

Answer 1

您使用的方法签名不正确。

• DbConfiguration.Loaded

  Public Shared Event Loaded As EventHandler(Of DbConfigurationLoadedEventArgs)
  

• DbConfigurationLoadedEventArgs.ReplaceService(Of TService)

  Public Sub ReplaceService(Of TService) (serviceInterceptor As Func(Of TService, Object, TService))
  

所以代码应该更像这样：

AddHandler Loaded,
    Sub(sender As Object, e As DbConfigurationLoadedEventArgs)
        e.ReplaceService(Of DbProviderServices)(
            Function(serviceInterceptor As DbProviderServices, o As Object)
                Return New CachingProviderServices(serviceInterceptor, transactionHandler, New DefaultCachingPolicy())
            End Function)
    End Sub

精简版：

AddHandler Loaded, Sub(sender As Object, e As DbConfigurationLoadedEventArgs) e.ReplaceService(Of DbProviderServices)(Function(serviceInterceptor As DbProviderServices, o As Object) New CachingProviderServices(serviceInterceptor, transactionHandler, New DefaultCachingPolicy()))