Public Class Form1
    Private WithEvents tmr As New Timer
    Private messageTime As New List(Of DateTime)
    Private ts As New TimeSpan
    Dim index As Integer = 0
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        messageTime.Add(New DateTime(Now.Year, Now.Month, Now.Day, 23, 20, 0))
        messageTime.Add(New DateTime(Now.Year, Now.Month, Now.Day, 23, 23, 0))
        messageTime.Add(New DateTime(Now.Year, Now.Month, Now.Day, 23, 34, 0))
        ts = messageTime(index) - Date.Now
        tmr.Interval = ts.TotalMilliseconds
        tmr.Start()
    End Sub
 
 
    Private Sub tmr_Tick(ByVal sender As Object, ByVal e As System.EventArgs) _
      Handles tmr.Tick
        MsgBox("Messagebox um: " & messageTime(index).ToString)
        index += 1
        If index < messageTime.Count Then
            ts = messageTime(index) - Date.Now
            tmr.Interval = ts.TotalMilliseconds
        Else
            tmr.Stop()
        End If
    End Sub
End Class

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