AddIfNotExists
An extension method for adding a value to a collection if it not exists yet.
Source
<Extension>
Public Sub AddIfNotExists(Of T)(list As ICollection(Of T), value As T)
If Not list.Contains(value) Then
list.Add(value)
End If
End SubExample
Dim exampleList As List(Of Long) From {1, 3}
'Value will not be added because value exists
exampleList.AddIfNotExists(1)
'Value will be added because value not exists
exampleList.AddIfNotExists(2)
'Values in list: 1, 2 3