'For Each' VB.NET iteration count

Question

Does a For Each loop in Visual Basic have an iteration count, or would I have to do that myself?

Answer 1

Unfortunately you have to do that yourself. The For Each construct uses an implementation the IEnumerator interface to iterate a sequence and the IEnumerator interface does not expose any members to indicate its position or current index within the sequence.

Answer 2

If I need an iterator variable, I use a for loop instead (every IEnumerable should have a .Count property).

Instead of

For Each element as MyType in MyList
    ....
Next

write

For i as integer = 0 to MyList.Count - 1
    element = MyList(i)
    ....
Next

which will be the same result. You have i as an iterator and element holds the current element.

Answer 3

If you are using Visual Studio 2009 (or VB.Net 9.0), you can use a Select override to get a count with the values.

For Each cur in col.Select(Function(x,i) New With { .Index = i, .Value = x })
 ...
Next