From: mynamehere@comcast.net   
      
   Some general comments and ideas to consider:   
   ---   
   Something like TotalPriceOfAllMaterials should probably be a method, not a   
   variable. Unless you have a serious performance problem, it will be cleaner to   
   actually add up all the material costs each time, rather than storing it and   
   trying to make sure it stays updated.   
   ---   
   If you are familiar with Interfaces, or willing to become so, they could make   
   your model easier. If you had an interface called IMaterial, for instance, then   
   the Assembly class and Material class could both implement it. This would allow   
   you to have a single collection that was a mixture of Assembly and Material   
   objects. I can explain more about it if you are interested - it is not   
   difficult   
   to do.   
   ---   
   Your Site class does not need to repeat the structure of an Asssembly - it can   
   simply contain one. So you could have   
      
    'Contents of Site   
   Public SiteAsm As clsAssembly   
      
   which would give you   
       SiteAsm.AssemblyAssemblies   
   and   
       SiteAsm.AssemblyMaterials   
      
   and avoid duplication of code.   
      
   Remember that your user does not have to know that the entire material   
   structure   
   of a site is being treated as a single assembly; it is just a programming   
   convenience. Object design should serve the programmer's purposes, not the end   
   user's. You could then put TotalPriceOfAllMaterials in the Assembly class, as   
   described in the post from Dikkie Dik.   
   ---   
   There is nothing wrong with adding an object reference to two collections (you   
   only need to make sure that you don't create a cross reference, where two   
   objects have references to each other).   
      
   So, if you are adding a clsMaterial object to some assembly, you can also add   
   it   
   to a separate MasterList:   
       Dim MasterList As clsMaterials   
       Dim Site As clsSite   
       Dim Mat As clsMaterial   
      
       Set Mat = New clsMaterial   
       Site.SiteAssemblies(2).AssemblyAssemblies(4).AssemblyMaterials.Add Mat   
       MasterList.Add Mat   
      
   This means you can find a material by drilling down through the Site structure,   
   or by looking in the MasterList. Both collections contain a reference to the   
   same object, so any changes to it would be seen from either vantage point. You   
   could even make MasterList a property of the Site class.   
   ---   
      
   "Iain Bishop"  wrote in message   
   news:lKyde.956$31.558@news-server.bigpond.net.au...   
   > I'm trying to model objects for the following problem:   
   >   
   > A building site contains assemblies, each of which can contain other   
   > assemblies and/or materials.   
   >   
   > I have modelled this using a Site class, Assembly class, and Material class   
   > as follows...   
   >   
   > Site Class (clsSite):   
   > Option Explicit   
   > 'General Details   
   > Public ProjectNumber As String   
   > Public SiteWBSCode As String   
   > Public SiteType As String   
   > Public LastUpdateFirstName As String   
   > Public LastUpdateSurname As String   
   > Public LastUpdateDate As Date   
   > Public TotalPriceOfAllMaterials As Double   
   > Public GeneralNotes As String   
   > 'Contents of Site   
   > Public SiteAssemblies As clsAssemblies 'a collection class of clsAssembly   
   > Public SiteMaterials As clsMaterials 'a collection class of clsMaterial   
   >   
   > Assembly Class (clsAssembly):   
   > Option Explicit   
   > 'General Details   
   > Public ID As Long   
   > Public QuantityRequested As Integer   
   > Public QuantityIssued As Integer   
   > 'Contents   
   > Public AssemblyAssemblies As clsAssemblies 'a collection class of   
   > clsAssembly   
   > Public AssemblyMaterials As clsMaterials 'a collection class of clsMaterial   
   >   
   > Material Class (clsMaterial)   
   > Option Explicit   
   > 'General Details   
   > Public InventoryCode As String   
   > Public Rate As Double   
   > Public QuantityRequested As Integer   
   > Public QuantityIssued As Integer   
   > Public TotalPrice As Double   
   > Public DateAmended As Date   
   >   
   > My questions are:   
   > 1. Have I modelled the problem correctly?   
   > 2. There is the potential for an infinite hierarchy of Assemblies - is this   
   > ok?   
   > 3. If so, I am having problems imagining how I would iterate through say all   
   > the materials to update their 'Rate' for example.   
   > 4. I'm also having problems imagining how I would go and find a material if   
   > its 'Quantity Requested' has changed, given that it could be any number of   
   > levels down.   
   >   
   > I've spent hours without making much progress. Please help if you know the   
   > answer to any of these questions.   
   >   
   > Many Thanks   
   > Iain   
   >   
   >   
      
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    * Origin: you cannot sedate... all the things you hate (1:229/2)