SUM property from list of lists using LINQ

Question

Hallo,

I am trying to get a sum of all "Total" form the object Item. I have list called "Areas" and it has the custom object "Items", it is the list of Item. and the Item has a property "Total"

I want to sum all the total from Areas. how can i do it?

Public Class AreaObj
    Public property Items as Items
End class

Public Class Areas
    Inherits System.ComponentModel.BindingList(Of AreaObj)
End class


Public Class Item
    Public property Total as integer
End class

Public Class Items
    Inherits System.ComponentModel.BindingList(Of Item)
End class

Thanks

Answer 1

Check this query:

Dim areas As Areas = . . .
Dim sum = areas.SelectMany(Function(a) a.Items).Sum(Function(i) i.Total)

It assumes that the objects are not Nothing.

Answer 2

thanks Viorel. It worked.