Question

I’m trying to move NServiceBus UnicastBusConfig from Web.config to (VB.NET) code and I’m having some problems doing so. The original Web.config looked like the following:

<UnicastBusConfig>
  <MessageEndpointMappings>
    <add Messages="Messages" Endpoint="TSInputQueue" />
  </MessageEndpointMappings>
</UnicastBusConfig>

And when the bus was configured with this, the “assembliesToEndpoints” property ended up looking like this and everything worked OK:

Then I removed the configuration from Web.config and created a new IConfigurationSource:

Public Class UnicastBusConfigurator
Implements IConfigurationSource

Public Function GetConfiguration(Of T As Class)() As T Implements NServiceBus.Config.ConfigurationSource.IConfigurationSource.GetConfiguration

    If (GetType(T) Is GetType(UnicastBusConfig)) Then

        Dim mapping = New MessageEndpointMapping()
        mapping.Endpoint = "InputQueue"
        mapping.Messages = "Messages"

        Dim unicastBusConfig As UnicastBusConfig = New UnicastBusConfig()
        unicastBusConfig.MessageEndpointMappings.Add(New MessageEndpointMapping())

        Return TryCast(unicastBusConfig, T)

    End If

    Return TryCast(ConfigurationManager.GetSection(GetType(T).Name), T)

End Function

End Class

And I added the following part to the bus initialization (for some reason the extension methods aren’t working…):

config = config.CustomConfigurationSource(New UnicastBusConfigurator)

I’ve made sure that the UnicastBusConfigurator’s GetConfiguration-method is executed, but the assembliesToEndpoints-property doesn’t look right:

Note the third row in HashTable, which is empty. Now, the config.CreateBus().Start() fails:

Spring.Objects.Factory.ObjectCreationException: Error creating object with name ‘NServiceBus.Unicast.UnicastBus’ : Error setting property values: PropertyAccessExceptionsException (1 errors); nested PropertyAccessExceptions are:
[Spring.Core.TypeMismatchException: Cannot convert property value of type [System.Collections.Hashtable] to required type [System.Collections.IDictionary] for property ‘MessageOwners’., Inner Exception: System.ArgumentException: Problem loading message assembly: —> System.ArgumentException: String cannot have zero length.

The exception seems to be caused by the empty row (“String cannot have zero length.”).

Any ideas about what I’m doing wrong?

Answer 1

I think the issue here is that code didn’t actually add the mapping to the collection. The code add a new empty MessageEndpointMapping. I think it should read:

unicastBusConfig.MessageEndpointMappings.Add(mapping)

This should give NSB something to map to.