Hi all,  
  
We have an ASP.NET 1.1 application running on IIS6 on Server 2003.  
  
Most of the base objects we are using in this application are taken from a  
  
windows application also written by us. We have used shared properties on  
  
some of these objects to enable caching of frequently used objects, so save  
  
fetching them from SQL every time. These shared properties vastly increase  
  
performance of our windows app.  
  
So in our web app, we have left the same caching technique, by using shared  
  
properties we cache various objects, usually in collections.  
  
These collections have been strongly typed by utilising seperate classes and  
  
storing an internal collection, e.g. see below.  
  
Public Class AttributeCollection  
  
Implements IEnumerable  
  
Protected intCollection As New Collection  
  
Public Overridable Sub Add(ByVal Attr As Attribute)  
  
intCollection.Add(Attr, Attr.Name)  
  
End Sub  
  
Public Sub Remove(ByVal Attr As Attribute)  
  
intCollection.Remove(Attr.Name)  
  
End Sub  
  
Public Sub Remove(ByVal AttrName As String)  
  
intCollection.Remove(AttrName)  
  
End Sub  
  
Public Function Count() As Integer  
  
Return intCollection.Count  
  
End Function  
  
Default ReadOnly Property Item(ByVal AttrName As String) As Attribute  
  
Get  
  
Return CType(intCollection.Item(AttrName), Attribute)  
  
End Get  
  
End Property  
  
Default ReadOnly Property Item(ByVal index As Integer) As Attribute  
  
Get  
  
Return CType(intCollection.Item(index), Attribute)  
  
End Get  
  
End Property  
  
Public Function GetEnumerator() As System.Collections.IEnumerator  
  
Implements System.Collections.IEnumerable.GetEnumerator  
  
Return intCollection.GetEnumerator  
  
End Function  
  
End Class  
  
The problem, is that at certain times, the cached collection returns  
  
containing nothing in the internal collection.  
  
So the shared Property is returning ok, and is pointing to one of the  
  
collections as shown above, however, the intcollection in the above code  
  
contains nothing. so the code falls over. We cannot explain why the internal  
  
collection for these objects is being emptied?  
  
Anyone any ideas?  
  
Thanks in advance and regards,  
  
Simon.