“不，我不知道，我也不知道。
我可以这样做

Private names As List(Of String)
Private keystrokes As New List(Of Char)()
Private processTimer As New System.Threading.Timer(AddressOf processAction, Nothing, -1, -1)

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    names = {"Aaron", "Allison", "Abdul", "Bob", "Orville"}.OrderBy(Function(s) s).ToList()
    ListBox1.DataSource = names
End Sub

Private Sub ListBox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles ListBox1.KeyPress
    e.Handled = True
    keystrokes.Add(e.KeyChar)
    processTimer.Change(250, -1)
End Sub

Private Sub processAction(state As Object)
    Dim searchString = New String(keystrokes.ToArray()).ToUpper()
    keystrokes.Clear()
    Dim match = names.FirstOrDefault(Function(name) name.ToUpper().StartsWith(searchString))
    If match = "" Then
        SelectListboxIndex(names.Concat({searchString}).OrderBy(Function(name) name).ToList().FindIndex(Function(name) name.ToUpper() = searchString.ToUpper()))
    Else
        SelectListboxIndex(names.FindIndex(Function(name) name.ToUpper() = match.ToUpper()))
    End If
End Sub

Private Sub SelectListboxIndex(index As Integer)
    If ListBox1.InvokeRequired Then
        ListBox1.Invoke(New Action(Of Integer)(AddressOf SelectListboxIndex), index)
    Else
        ListBox1.SelectedIndex = Math.Max(Math.Min(index, ListBox1.Items.Count - 1), 0)
    End If
End Sub

不知道为什么要aaa选择Allison，但逻辑可以修改。