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copied!<p>By calling the method each time that you use the collection, what your code is effectively doing is:</p> <pre><code>For i As Integer = 0 To csB.Count - 1 Dim cc As Collection(Of Reports_ucColumn) If csB(i).Contains("Invalid") Or csB(i).Contains("Duplicate") Then cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).isValid = False cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).title = csB(i) If csB(i).Contains("Invalid") Then cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).errCode = "005W" Else cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).errCode = "005W" 'todo - chg this once we get a duplicate col err code End If Else cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).isValid = True cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).title = csB(i) cc = New Collection(Of Reports_ucColumn) cc.Add(Me.ucColumn0) cc.Add(Me.ucColumn1) cc.Add(Me.ucColumn2) cc.Item(i).errCode = String.Empty End If Next </code></pre> <p>You would never write code like that, would you?</p> <p>You can turn the function into a property with lazy initialisation. Then it's ok to use it over and over, as the collection is only created once:</p> <pre><code>Private _cc As Collection(Of Reports_ucColumn) Private Property CcB As Collection(Of Reports_ucColumn) Get If _cc Is Nothing Then _cc = New Collection(Of Reports_ucColumn) _cc.Add(Me.ucColumn0) _cc.Add(Me.ucColumn1) _cc.Add(Me.ucColumn2) End If Return _cc End Get End Property </code></pre> <p>(Ideally the property should be public in a class and the <code>_cc</code> variable should be private, encapsulated in the class so that only the property could access it.)</p> <p>Semantically this works fine also. A function generally does a bit of work, so you shouldn't call it over and over if you want to use the result over and over. A property on the other hand usually doesn't do much work, and if the result needs some processing to be created, the property usually does something like lazy initialisation or pre-initialisation to make sure that the work isn't done more than neccessary.</p>

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