Listbox Multiple KeyPress

Question

How can I achieve the search functionality that works with multiple keys in CheckedListBox and ListBox?

Example: I have the following items in the list:

1000 1500 1520 2010 5001 5102

When I press the key 1, instantly search the first hit that match with the first char that starts with '1'.

But, If I want locate the item "5102", the list only will can search the 5, and then, I need go manually to identify the wanted item.

Answer 1

Answering to my own question. This it's a clean solution that doesn't need too much work (All the code can handle in the KeyDown event):

Sub DropDownListBox_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs)
    If Char.IsLetterOrDigit(Chr(e.KeyValue)) Then
        e.SuppressKeyPress = True
        If TryCast(sender.tag, Timer) Is Nothing Then
            Dim vTimer As New Timer

            vTimer.Interval = 1000
            vTimer.Tag = ""
            sender.Tag = vTimer

            AddHandler vTimer.Tick,
                Sub(Timer As Object, eventsArgs As System.EventArgs)
                    Timer.Tag = ""

                    If Not TryCast(sender, CheckedListBox).Visible Then
                        Timer.dispose() : Timer = Nothing
                    End If
                End Sub
        Else
            sender.Tag.Stop() : sender.Tag.Start()
            sender.Tag.Tag &= Chr(e.KeyValue)

            Dim vIndex As Integer = TryCast(sender, CheckedListBox).FindString(sender.Tag.Tag)

            If vIndex <> -1 Then TryCast(sender, CheckedListBox).SelectedItem = TryCast(sender, CheckedListBox).Items(vIndex)
        End If
    End If
End Sub

Basically I use the TAG object to keep a Timer running every 1 sec; then, if the user typing several chars, the process will find exactly the wanted text.

Any comment or feedback will be welcome.

Answer 2

Public Class Form1
    Dim Type As String
    Private Sub ListBox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles ListBox1.KeyPress
        If Asc(e.KeyChar) <> 8 Then
            If Asc(e.KeyChar) < 65 Or Asc(e.KeyChar) > 122 Then
                e.Handled = True
                ' Clear String at Escape key press & Reset Listbox location
                If Asc(e.KeyChar) = 27 Then
                    Type = ""
                    ListBox1.SelectedIndex = -1
                    ListBox1.SelectedItem = ListBox1.SelectedIndex
                End If
            End If
            If Asc(e.KeyChar) = 27 Then
                ' Do not add escape key char to string at key press
            Else
                ' add char one by one after key press
                Type &= e.KeyChar
                Dim TL As Integer = Type.Length
                Dim i As Integer = 0
                For i = 0 To ListBox1.Items.Count - 1
                    ' match key press in total items in listbox
                    'MsgBox(Format$(Mid$(ListBox1.Items(i), 1, TL)))
                    If Format$(Mid$(ListBox1.Items(i), 1, TL)) = Type Then
                        ListBox1.SelectedIndex = i
                    End If
                Next
            End If
        End If
    End Sub
End Class