VB.NET - How to Lock the Object in VB.NET

Hi Experts,

I want to lock the object of a class.
i have written a code like :

          Dim objLock As New Object
              SyncLock objLock
                Show(data, False)
              End SyncLock

as soon as show method is being executed, some of my background threads are changing data.
so that i am getting error.
to prevent that from what should i do..
help me..
Thanks in advance..

Regards,
Nani

Use the Lock method, not SyncLock