Strange Exception : String reference not set to an instance of a String. Parameter name: s

[cemremengu]

This works OK

_builder = new ContainerBuilder();

_builder.RegisterInstance(
    BusClientFactory.CreateDefault()).As<IBusClient>().SingleInstance(); 

But this throws an exception with a not really helpful error:

_builder = new ContainerBuilder();

_builder.RegisterInstance(
    BusClientFactory.CreateDefault(new RawRabbitConfiguration
    {
        Username = "guest",
        Password = "guest",
        Port = port,
        Hostnames = new List<string> {host}
    })).As<IBusClient>().SingleInstance();

Exception

String reference not set to an instance of a String.
Parameter name: s

Stacktrace

   at RawRabbit.Channel.ChannelFactory..ctor(IConnectionFactory connectionFactory, RawRabbitConfiguration config, ChannelFactoryConfiguration channelConfig)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ConstructorCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ConstructorCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.Internal.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
   at Microsoft.Extensions.Internal.ActivatorUtilities.CreateInstance[T](IServiceProvider provider, Object[] parameters)
   at RawRabbit.vNext.IServiceCollectionExtensions.<>c.<AddRawRabbit>b__0_0(IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
   at RawRabbit.vNext.BusClientFactory.CreateDefault(IServiceCollection services)
   at RawRabbit.Topshelf.RawShelf`1..ctor(String host, UInt16 port) in C:\Users\CMENGU\Desktop\RawRabbit.Topshelf\src\RawRabbit.Topshelf\RawShelf.cs:line 18
   at RawRabbit.Topshelf.Demo.Program.Main(String[] args) in C:\Users\CMENGU\Desktop\RawRabbit.Topshelf\src\RawRabbit.Topshelf.Demo\Program.cs:line 12

I am probably doing something wrong but error doesn't really say what's going on

[pardahlman]

If you just new up the configuration all strings will have their default values (null). My guess is that you haven't declared Vhost, which cannot be null.

[cemremengu]

Yes that is correct ! @pardahlman