Timer定时器不能关联使用

Question

我想用Timer定时器做个PLC通讯程序，在Timer1_tick事件里关闭timer2(看门狗定时器)写给PLC发送的命令，发送完命令后关闭timer1并立即开启Timer2(当做看门狗来用)，等待serialport_datareceived事件，在serialport_datareceived事件中关闭看门狗timer2,读取串口数据、校验数据并将数据写入数据库。如果timer2设定的时间内没有serialport_datareceived事件发生，用timer2_tick事件重新启动timer1.但是发现serialport_datareceived事件没能将timer1重启，timer2也没能将timer1重启。

 Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer2.Enabled = False
        Timer1.Enabled = False
        SendMessage()
        Timer2.Enabled = True
    End Sub
    Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        Timer2.Enabled = False
        SerialPort1.Read()
        CheckData()
        WriteDataBase()
        Timer2.Enabled = True
    End Sub
    Private Sub Timer2_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        Timer1.Enabled = True
    End Sub

Answer 1

timer1无法重启，好像SerialPort_Datareceived事件无法重启timer1

Public Class MainForm
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Interval = 500
        Timer2.Interval = 1000
        myserialPort.PortName = "COM2"
        myserialPort.BaudRate = 9600
        myserialPort.Parity = IO.Ports.Parity.None
        myserialPort.DataBits = 8
        myserialPort.StopBits = 1
        Timer1.Enabled = True
    End Sub
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer1.Enabled = False
        Label1.BackColor = Color.Red
        myserialPort.Write(".....") '写数据
        Timer2.Enabled = True
    End Sub
    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        Timer2.Enabled = False
        Label1.BackColor = Color.Blue
        Timer1.Enabled = True
    End Sub
    Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles myserialPort.DataReceived
        Timer2.Enabled = False
        myserialPort.Read() '读数据
        Timer1.Enabled = True
    End Sub
End Class

Answer 2

在我这里测试了一下，倒是没什么问题，Timer正确的被启动和停止。不过建议你使用System.Timers里面的TImer类，功能更多更强大~http://msdn.microsoft.com/zh-cn/library/system.timers.timer

Public Class Form1
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer2.Enabled = False
        Timer1.Enabled = False
        Console.WriteLine("Timer1 Now in DISABLED")
        Console.WriteLine("Timer1" & Timer1.Enabled.ToString)
        Timer2.Enabled = True
        Console.WriteLine("Timer2 Now in ENABLED")
        Console.WriteLine("Timer2" & Timer2.Enabled.ToString)

        Console.WriteLine("Timer11111111----------------------------------------")
    End Sub
    Private Sub Timer2_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        Timer1.Enabled = True
        Console.WriteLine("Timer1 Now is  ENABLED")
        Console.WriteLine("Timer1" & Timer1.Enabled.ToString)
        Console.WriteLine("Timer22222222222-------------------------------------")
    End Sub

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Timer1.Interval = 500
        Timer2.Interval = 1000

        Timer1.Enabled = True
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Timer2.Enabled = False
        Console.WriteLine("Timer1 Now in ENABLED")
        Console.WriteLine("Timer1" & Timer1.Enabled.ToString)
        '....
        Timer2.Enabled = True
        Console.WriteLine("Timer2 Now in ENABLED")
        Console.WriteLine("Timer2" & Timer2.Enabled.ToString)
        Console.WriteLine("Buttonnnnnnnnnnnnnnnn-------------------------------------")
    End Sub
End Class

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