Sub Main(ByVal args() As String)
    Dim categoryName As String = ""
    Dim counterName As String = ""

    Dim idColCol As InstanceDataCollectionCollection

    ' Copy the supplied arguments into the local variables.
    Try
        categoryName = args(0)
        counterName = args(1)
    Catch ex As Exception
        ' Ignore the exception from non-supplied arguments.
    End Try

    Try
        ' Get the InstanceDataCollectionCollection for this category.
        Dim pcc As New PerformanceCounterCategory(categoryName)
        idColCol = pcc.ReadCategory()
    Catch ex As Exception
        Console.WriteLine( _
            "An error occurred getting the InstanceDataCollection for " & _
            "category ""{0}""." & vbCrLf & ex.Message, categoryName)
        Return
    End Try

    ' Check if this counter name exists using the Contains
    ' method of the InstanceDataCollectionCollection.
    If Not idColCol.Contains(counterName) Then
        Console.WriteLine( _
            "Counter ""{0}"" does not exist in category ""{1}"".", _
            counterName, categoryName)
        Return
    Else
        ' Now get the counter's InstanceDataCollection object using the
        ' indexer (Item property) for the InstanceDataCollectionCollection.
        Dim countData As InstanceDataCollection = idColCol(counterName)

        Dim idColKeys As ICollection = countData.Keys
        Dim idColKeysArray(idColKeys.Count - 1) As String
        idColKeys.CopyTo(idColKeysArray, 0)

        Console.WriteLine("Counter ""{0}"" of category ""{1}"" " & _
            "has {2} instances.", counterName, categoryName, idColKeys.Count)

        ' Display the instance names for this counter.
        Dim index As Integer
        For index = 0 To idColKeysArray.Length - 1
            Console.WriteLine("{0,4} -- {1}", index + 1, idColKeysArray(index))
        Next index
    End If
End Sub