.NET (Core and Framework)

Public Class Form1
    Dim Drag, boolShortBreak, boolLongBreak As Boolean
    Dim X As Integer
    Dim Y As Integer

    'Set Alarm Time for 15 Minutes (Is seconds to reduce countdown when testing
    Public Shared alarmTime15 As Date = Date.Now.AddSeconds(15)
    'Set Alarm Time for 30 Minutes
    Public Shared alarmTime30 As Date = Date.Now.AddMinutes(30)

    'Update Label to show system time
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrSystemTime.Tick
        Label4.Text = TimeOfDay

        'Check Date Time Picker if value matches system time
        CheckDTP()
    End Sub

    'No form border style present
    'If mouse down get Mouse position
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        Drag = True
        X = Windows.Forms.Cursor.Position.X - Me.Left
        Y = Windows.Forms.Cursor.Position.Y - Me.Top
    End Sub

    'No form border style present
    'Get position of form when mouse is dragged(mouse down)
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If Drag = True Then
            Me.Left = Windows.Forms.Cursor.Position.X - X
            Me.Top = Windows.Forms.Cursor.Position.Y - Y
        End If

    End Sub

    'Release form from being dragged on mouse up
    Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseUp
        Drag = False
    End Sub

    '15 minute timer subtracted from system time
    Private Sub tmrStart15_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrStart.Tick
        Select Case True

            'date time picker bool for short break (implies 15min break)
            Case boolShortBreak

                Dim remainingTime15 As TimeSpan = alarmTime15.Subtract(Date.Now)
                Label5.Text = String.Format("{0}:{1:d2}:{2:d2}", remainingTime15.Hours, remainingTime15.Minutes, remainingTime15.Seconds)

                'If 15min reaches zero, stop timer and set bool to false
                If remainingTime15.Duration.Seconds = 0 Then
                    Stop_Clock()
                    boolShortBreak = False
                End If
                'date time picker bool for long break (implies 30min break)
            Case boolLongBreak

                Dim remainingTime30 As TimeSpan = alarmTime30.Subtract(Date.Now)
                Label5.Text = String.Format("{0}:{1:d2}:{2:d2}", remainingTime30.Hours, remainingTime30.Minutes, remainingTime30.Seconds)

                'If 30min reaches zero, stop timer and set bool to false
                If remainingTime30.Duration.Seconds = 0 Then
                    Stop_Clock()
                    boolLongBreak = False
                End If
        End Select
    End Sub

    'Check if date time picker values match system time
    'If so enable timer based on either 15min break or 30min break
    'using select case within the tmrStart

    'bools choose whether it is a 15min break or 30min break
    Public Sub CheckDTP()
        If dtp1.Text = Label4.Text Then
            boolShortBreak = True
            tmrStart.Enabled = True
        End If

        If dtp2.Text = Label4.Text Then
            boolLongBreak = True
            tmrStart.Enabled = True
        End If

        If dtp3.Text = Label4.Text Then
            boolShortBreak = True
            tmrStart.Enabled = True
        End If
    End Sub

    'Used to stop the tmrStart Timer
    Private Sub Stop_Clock()
        tmrStart.Stop()
        tmrStart.Enabled = False
    End Sub

End Class