Public Class frmDoubleInput
 
    Dim WithEvents timInput As New Timer With {.Enabled = True, .Interval = 500}
    Dim lstItems As New ListBox With {.Parent = Me, .Width = 100, .Height = 200}
    Dim lastinput As Date = Now
    Dim selectedindex As Integer = -1
    Dim doubleclick_interval As New TimeSpan(0, 0, 1)
 
    Private Sub frmDoubleInput_Load(sender As System.Object, _
                    e As System.EventArgs) Handles MyBase.Load
 
        Me.KeyPreview = True
        For i As Integer = 0 To 99
            lstItems.Items.Add(i.ToString)
        Next i
    End Sub
 
 
    Private Sub frmMain_KeyDown(sender As Object, _
                    e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
 
        If (e.KeyCode >= Keys.NumPad0 And e.KeyCode <= Keys.NumPad9) AndAlso _
          e.Control Then
            If New TimeSpan(Now.Ticks - lastinput.Ticks) > _
            doubleclick_interval Then selectedindex = 0
            lastinput = Now
            If selectedindex > 9 Then selectedindex = 0
            selectedindex *= 10
            selectedindex += CType(e.KeyCode, Integer) - 96
        End If
    End Sub
 
 
    Private Sub Timer1_Tick(sender As System.Object, _
                e As System.EventArgs) Handles timInput.Tick
 
        If selectedindex >= 0 And selectedindex < lstItems.Items.Count Then
            If New TimeSpan(Now.Ticks - lastinput.Ticks) > _
              doubleclick_interval Then
                lstItems.SelectedIndex = selectedindex
                selectedindex = -1
                lstItems.Refresh()
            End If
        End If
 
    End Sub
End Class