Public Class Form1
    Private WithEvents Timer As New Timer

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Fai in modo che l' evento Timer_Tick avvenga ogni secondo
        Timer.Interval = 1000
        'Avii il Timer
        Timer.Start()
    End Sub


    Private Sub Timer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer.Tick
        If Now.ToShortTimeString = Me.DateTimePicker1.Value.ToShortTimeString Then
            MsgBox("Ciao")
        End If
    End Sub


End Class