It is a constructor for a class.
VB Code:
Public class Cat
private _MyName as string = nothing
'###########
Public Sub New(byval name as string)
_MyName = name
End Sub
'###########
Public Sub Meow()
MessageBox.Show("Meow, my name is " & _MyName)
End Sub
End Class
Then use this to demonstrate it...
VB Code:
Dim MyCat as cat = New Cat("Tiddles")
MyCat.Meow()
A constructor is used to specify zero or more parameters of a class (VB6 did not support Constructors) and is also used to set up the class so its ready for use.
Constructors can be a complex topic as they can be used for a lot of different things, and classes can even have multiple constructors, each with a different set of parameters.