D_Bester - 8 months ago 57

Vb.net Question

I have a list of lists (StoreList). I need a count of all available apples across all stores. Not sure how to do that.

`Class myObject`

Public What As String

Public Available As Boolean

End Class

Public Sub Test()

Dim ItemList As New List(Of myObject)

ItemList.Add(New myObject With {.What = "Apple", .Available = True})

ItemList.Add(New myObject With {.What = "Cherry", .Available = False})

Dim StoreList As New List(Of List(Of myObject))

StoreList.Add(ItemList)

'StoreList.Add(...)

'error here

Dim count As Integer = StoreList.Sum( _

ItemList.Where(Function(x As myObject) _

x.What = "Apple" And x.Available).Count)

End Sub

Obviously I can't sum a count the way I'm doing it. How would I use Linq to get a count of all available apples across all stores?

Answer

You have forgot to assign the function in the `Sum`

try this:

```
Dim count As Integer = StoreList.Sum( Function(inner) _
inner.Where(Function(x As myObject) _
x.What = "Apple" And x.Available).Count)
```

Source (Stackoverflow)