MvcMiniProfiler无法强制转换EFProfiledDbConnection类型的对象

Question

我正在尝试将MvcMiniProfiler集成到我的asp.net mvc+entity framewok项目中。第一次web请求一切正常，但在其他请求时却出现异常。

我的项目是

MVC 3

实体框架4.1 (DatabaseFirst + POCO生成器DbContext)

MvcMiniProfiler.dll 1.9.0.0

MvcMiniProfiler.EntityFramework.dll 1.9.1.0

我从Nu-Get安装MvcMiniProfiler

添加到下面的global.asax

    protected void Application_BeginRequest()
    {
        if (Request.IsLocal)
        {
            MvcMiniProfiler.MiniProfiler.Start();
            MiniProfilerEF.Initialize();       
        }
    }

添加到下面的web.config

   <system.data>
    <DbProviderFactories>
      <remove invariant="MvcMiniProfiler.Data.ProfiledDbProvider" />
      <add name="MvcMiniProfiler.Data.ProfiledDbProvider" invariant="MvcMiniProfiler.Data.ProfiledDbProvider" description="MvcMiniProfiler.Data.ProfiledDbProvider" type="MvcMiniProfiler.Data.ProfiledDbProviderFactory, MvcMiniProfiler, Version=1.8.0.0, Culture=neutral, PublicKeyToken=b44f9351044011a3" />
    </DbProviderFactories>
  </system.data>

我得到了这个异常

    System.InvalidCastException was unhandled by user code
  Message=Unable to cast object of type 'MvcMiniProfiler.Data.EFProfiledDbConnection' to type 'System.Data.SqlClient.SqlConnection'.
  Source=System.Data
  StackTrace:
       at System.Data.SqlClient.SqlCommand.set_DbConnection(DbConnection value)
       at System.Data.Common.DbCommand.set_Connection(DbConnection value)
       at MvcMiniProfiler.Data.ProfiledDbCommand.set_DbConnection(DbConnection value) in C:\Users\sam\Desktop\mvc-mini-profiler\MvcMiniProfiler\Data\ProfiledDbCommand.cs:line 118
       at System.Data.Common.DbCommand.set_Connection(DbConnection value)
       at System.Data.Common.Utils.CommandHelper.SetStoreProviderCommandState(EntityCommand entityCommand, EntityTransaction entityTransaction, DbCommand storeProviderCommand)
       at System.Data.EntityClient.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
       at System.Data.Objects.Internal.ObjectQueryExecutionPlan.Execute[TResultType](ObjectContext context, ObjectParameterCollection parameterValues)

EF调用中发生异常

ModaEntitiesWrapper.GetInstance().Articles
               .AsNoTracking()
               .Where(p => p.StatusId == 1).ToList();

如果我将Web.Config中MvcMiniProfiler.Data.ProfiledDbProvider版本从1.8.0.0更改为1.9.0.0，则在MiniProfilerEF.Initialize()调用中发生新类型的异常。

System.IndexOutOfRangeException was unhandled by user code
  Message=The given DataRow is not in the current DataRowCollection.
  Source=System.Data
  StackTrace:
       at System.Data.DataRowCollection.Remove(DataRow row)
       at MvcMiniProfiler.MiniProfilerEF.Initialize() 

Answer 1

也许这会有帮助。将MiniProfilerEF.Initialize();移到方法Application_Start()的顶部。请注意，在EF 4.1和更高版本中，调用的方法应该是MiniProfilerEF.Initialize_EF42();。

protected void Application_Start() {
    Logger.Info("Application start");
    MiniProfilerEF.Initialize_EF42();
    // ...
}

Answer 2

查看http://code.google.com/p/mvc-mini-profiler/

下面是一个如何将mvc-mini-profiler与EF数据库一起使用的示例：

public static class Entities
{
    public static MyEntities Create()
    {
         var builder = new EntityConnectionStringBuilder(ConfigurationManager.ConnectionStrings["MyEntities"].ConnectionString);
         var sqlConnection = new SqlConnection(builder.ProviderConnectionString);
         var profiledConnection = new EFProfiledDbConnection(sqlConnection, MiniProfiler.Current);

         return profiledConnection.CreateObjectContext<MyEntities>();
    }
}

然后，您可以使用该方法向IOC容器注册您的实体，或者使用类似于

using(var entities = Entities.Create())
{
    //Do stuff here
    entities.SaveChanges();
}

编辑:忘记添加

MiniProfilerEF.Initialize()；

它只首先用于EF代码。