Unable to cast object of type 'MvcMiniProfiler.Data.EFProfiledDbConnection' to type 'System.Data.SqlClient.SqlConnection'

Question

Unable to cast object of type 'MvcMiniProfiler.Data.EFProfiledDbConnection' to type 'System.Data.SqlClient.SqlConnection'.

I am trying to upgrade to MvcMiniProfiler 1.9.0 and I keep getting this when I call MiniProfilerEF.Initialize(). I have removed the system.data config section. I don't know what I am doing wrong. I have followed the steps on the site, but maybe I missed something?

I am using EF code first 4.1 and I am passing in the name of my connectionstring into a constructor to create my datacontext.

Web Activator

using Project.Web.App_Start;
using WebActivator;

[assembly: PreApplicationStartMethod(typeof(MiniProfiler), "Start")]

namespace Project.Web.App_Start {
    public class MiniProfiler {
        public static void Start()
        { 
            if (Eco.Environment.IsDevelopment) {
                MiniProfilerEF.Initialize();
            }
        }
    }
}

StructureMap Registry:

using Project.Domain.Repositories;
using StructureMap.Configuration.DSL;

namespace Project.Web.DependencyResolution.Registries {
public class RepositoriesRegistry : Registry {
    public RepositoriesRegistry() {
        For<IProjectDataContext>().HybridHttpOrThreadLocalScoped().Use(() => new ProjectDataContext(Eco.Database.Name));
          }
    }
}

DataContext Constructor:

    public ProjectDataContext(string nameOrConnectionString)
        : base(nameOrConnectionString) {
        Active = new Active(this);
    }

I have removed system.data dataproviders fron my config since the documentation says I only need to call MiniProfilerEF.Initialize().

**Update

Previously in 1.7 MvcMiniProfiler I had to set the Database.DefaultConnectionFactory property, but I've removed that. The Database.DefaultConnectionFactory always comes back as SqlConnectionFactory, shouldn't it be ProfiledConnectionFactory or something like that?

Answer 1

I was seeing this same error. It drove me nuts but I finally figured it out. My issue had nothing to do with web.config, assemblies, Initialize_42 or Initialize(false) hacks or anything.

Here's where I went wrong...

I had enabled automatic application of migrations like this:

App_Start:

Database.SetInitializer(
    new MigrateDatabaseToLatestVersion<DataContext, Migrations.Configuration>()
);

Migrations/Configuration.cs:

internal sealed class Configuration 
    : DbMigrationsConfiguration<Path.To.DataContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
    }
}

And that was being triggered via WebActivator like this:

[assembly: WebActivator.PreApplicationStartMethod(
    typeof(service_tracker_mvc.App_Start.DatabaseInitializer), "Start")]

I accidentally found that disabling this process resulted in the profiler working. The issue, as it happens, is that this init process was happening too soon. It normally happens during Application_Start (if you're not using this fancy WebActivator stuff) so I changed it to PostStart. Now it works:

                        ▼▼▼▼
[assembly: WebActivator.PostApplicationStartMethod(
    typeof(service_tracker_mvc.App_Start.DatabaseInitializer), "Start")]

Answer 2

I made the mistake of adding MiniProfiler.EF rather than MiniProfiler.EF6. Removing MiniProfiler.EF and replacing it with the EF6 version fixed my issue.