Is it possible to iterate over two IEnumerable objects at the same time?

Question

If I have a List(Of x) and a List(Of y) is it possible to iterate over both at the same time?

Something like

for each _x as X, _y as Y in List(of x         


        

Answer 1

No, not in vb.net with the vb loop constructs.

You can however do it yourself with the enumerators:

    Sub MyOwnIENumeration()
    Dim a As List(Of String), b As List(Of String)
    Dim EnmA As System.Collections.Generic.IEnumerator(Of String) = a.GetEnumerator
    Dim EnmB As System.Collections.Generic.IEnumerator(Of String) = b.GetEnumerator

    If EnmA.MoveNext() And EnmB.MoveNext() Then
        Do
            If EnmA.Current = EnmB.Current Then
                Debug.Print("list matched on " & EnmA.Current)
                If Not EnmA.MoveNext() Then Exit Do
                If Not EnmB.MoveNext() Then Exit Do
            ElseIf EnmA.Current < EnmB.Current Then
                If Not EnmA.MoveNext() Then Exit Do
            Else
                If Not EnmB.MoveNext() Then Exit Do
            End If
        Loop
    End If

    EnmA.Dispose() : EnmB.Dispose()
End Sub