Note that you can use UBound to find the upper bound of a control array. For example, if lblName is a control array, then lblName.LBound and lblName.UBound give the array's lower and upper bounds.

However, this does not mean every index is defined in between. Controls with indexes 0 and 5 may be loaded while no other controls are loaded.

Private Sub cmdTest_Click()
Dim idx As Integer
Dim lft As Single

    idx = CInt(txtIndex.Text)
    On Error Resume Next
    lft = lblControl(idx).Left
    If Err.Number <> 0 Then
        MsgBox "This control does not exist."
    Else
        MsgBox "This control is loaded."
    End If
End Sub