Execute a method on an existing process instance. Vb.Net - vb.net

Question

I have a windows service that I have been writing in Vb.Net. As part of this service it calls a class that has a long running Process.
I can execute commands to this process when I want to via the ServerCommands() class within the service, however I want to call these remotely. Possibly from a website or click once WPF application.
For this I have used a simple Tcp.Ip WCF example, and have verified it as working correctly.
This called OnStart()
Private _serverCommands As ServerCommands
Protected Overrides Sub OnStart(ByVal args() As String)
' Add code here to start your service. This method should set things
' in motion so your service can do its work.
Debugger.Launch()
' Action a new implementaion of the WCF Service on localhost
_host.AddServiceEndpoint(GetType(ICommunicationService), New NetTcpBinding(), String.Format("net.tcp://127.0.0.1:{0}", AppSettings.TcpServicePort))
_host.Open()
' Start the server command
_serverCommands = New ServerCommands()
_serverCommands.StartServer()
End Sub
However... when I'm calling the service through WCF its starting a new instance of the ServerCommands() Class rather than attaching to the already running thread.
The following call
Public Function DoWork() As String Implements ICommunicationService.DoWork
Dim command As String = "say hello world"
Dim service As IMinecraftService = New MinecraftService()
service.ExecuteServerSideCommand(command)
Return "Command Executed"
End Function
Implements this on the main service.
Public Sub ExecuteServerSideCommand(command As String) Implements IMinecraftService.ExecuteServerSideCommand
If (_serverCommands IsNot Nothing) Then
_serverCommands.SendCommand(command)
End If
End Sub
It appears that in debug _serverCommands is Nothing when it should be running.
How might I go about ensuring any command I execute through WCF communicates with the running instance instead of creating a new ServerCommand() instance??
I haven't tried WCF before, so I might be hitting a dead end... however I'm sure its possible.
Thanks in advance.

Answer 1

I found that I was calling a new instance of the MinecraftService each time I sent a command via WCF.
As Jeff rightly said, I was not making the object shared, I was only accessing a new instance of this class.
I changed it from
From
MyMainClass
Private _serverCommands As ServerCommands
My WcfService
Dim command As String = "say hello world"
MinecraftService.ServerCommands.SendCommand(command)
To
MyMainClass
Public Shared ServerCommands As ServerCommands
My WcfService
MinecraftService.ServerCommands.SendCommand(command)