System.Timers.Timer 用法 [英] System.Timers.Timer Usage
问题描述
为了这个问题的目的，我完整地包括了我的一类:
For the purposes of this question I'm including a class of mine in its entirety:
public class SerialPortConnection
{
private SerialPort serialPort;
private string ping;
double failOut;
bool isReceiving;
public SerialPortConnection(string comPort = "Com1", int baud = 9600, System.IO.Ports.Parity parity = System.IO.Ports.Parity.None, int dataBits = 8, System.IO.Ports.StopBits stopBits = System.IO.Ports.StopBits.One, string ping = "*IDN?", double failOut = 2)
{
this.ping = ping;
this.failOut = failOut * 1000;
try
{
serialPort = new SerialPort(comPort, baud, parity, dataBits, stopBits);
}
catch (Exception e)
{
throw e;
}
}
//Open Serial Connection. Returns False If Unable To Open.
public bool OpenSerialConnection()
{
//Opens Initial Connection:
try
{
serialPort.Open();
serialPort.Write("REMOTE\r");
}
catch (Exception e)
{
throw e;
}
serialPort.Write(ping + "\r");
var testReceived = "";
isReceiving = true;
Timer StopWatch = new Timer(failOut);
StopWatch.Elapsed += new ElapsedEventHandler(OnTimedEvent);
StopWatch.Interval = failOut;
StopWatch.Enabled = true;
while (isReceiving == true)
{
try
{
testReceived += serialPort.ReadExisting();
}
catch (Exception e)
{
throw e;
}
}
StopWatch.Dispose();
if (testReceived.Contains('>'))
{
return true;
}
else
{
return false;
}
}
public string WriteSerialConnection(string SerialCommand)
{
try
{
serialPort.Write(String.Format(SerialCommand + "\r"));
var received = "";
bool isReceiving = true;
Timer StopWatch = new Timer(failOut);
StopWatch.Elapsed += new ElapsedEventHandler(OnTimedEvent);
StopWatch.Interval = failOut;
StopWatch.Enabled = true;
while (isReceiving == true)
{
try
{
received += serialPort.ReadExisting();
}
catch (Exception e)
{
throw e;
}
}
if (received.Contains('>'))
{
return received;
}
else
{
received = "Error: No Data Received From Device";
return received;
}
StopWatch.Dispose();
}
catch (Exception e)
{
throw e;
}
}
//Closes Serial Connection. Returns False If Unable To Close.
public bool CloseSerialConnection()
{
try
{
serialPort.Write("LOCAL\r");
serialPort.Close();
return true;
}
catch (Exception e)
{
throw e;
}
}
private void OnTimedEvent(object source, ElapsedEventArgs e)
{
isReceiving = false;
}
}
我在这里尝试做的是让循环运行一段设定的时间(在这种情况下为两秒)，因为连接到我正在使用的串行端口的设备是不可预测的.我不知道我会从中收到什么数据，也不知道需要多长时间.这是无法修复的，这是我必须处理的事情.目前，我最好的选择是等待一段时间并检查我收到的数据以获取结束令牌 (">").我什至在课堂上也试过像这样连接计时器:
What I'm attempting to do here is keep a loop running for a set amount of time (two seconds in this case) because the device connected to the serial port I'm working with is unpredictable. I don't know what data I will receive from it and I don't know how long it will take. That can't be fixed and is something I have to work with. My best option, currently, is to wait a set amount of time and check the data I've received for an end token (">"). I've tried wiring up a timer even in the class like so:
Timer StopWatch = new Timer(failOut * 1000);
StopWatch.Elapsed += new ElapsedEventHandler(OnTimedEvent);
StopWatch.Interval = failOut;
StopWatch.Enabled = true;
但它似乎不起作用.事件本身看起来像这样:
But it doesn't appear to work. The event itself looks like so:
private void OnTimedEvent(object source, ElapsedEventArgs e)
{
isReceiving = false;
}
我的目标是切断与 isReceiving 相关的循环:
My objective is to cut the loop isReceiving is tied to:
(while isReceiving == true)
{
//Do Something
}
但它似乎不起作用.我想我完全误解了计时器的功能，但我之前有过实现它的建议.我究竟做错了什么?如果我只是完全滥用它，我可以用什么来代替计时器?正如我所说，我别无选择，只能等待一段时间并检查我收到的内容.除了等待并希望我得到一些东西之外，无法以任何方式避免或处理这种情况.
But it doesn't appear to work. I assume I've completely misunderstood the function of the timer but I've had suggestions before to implement it. What am I doing wrong? If I'm just completely misusing it, what can I use instead of a timer? As I've said, I've no choice but to wait a set amount of time and check what I've received. That can't be avoided or handled in any way other than waiting and hoping I get something.
也许我最好澄清一下.OnTimedEvent 事件正在触发，变量设置为 false，但它不会切断循环，因为 isReceiving 未设置为 false.
Maybe it's best I clarify this. The OnTimedEvent event is firing and the variable is set to false but it doesn't cut the loop as isReceiving isn't getting set to false.
编辑 2:
先生Passant 的回答非常有效，除非我遇到了一个奇怪的错误.由于我不认为这是他的答案中的问题，更有可能是硬件缺陷，或者其他一些奇怪和晦涩的东西，我将他的答案标记为已接受.我建议任何选择实施他的答案的人也可以查看我在此处提交的问题:
Mr. Passant's answer works beautifully barring a strange error I'm encountering. As I don't believe it's a problem within his answer, it's more likely that it's a hardware flaw, or something else strange and obscure along those lines, I'm leaving his answer marked as accepted. I recommend anyone that chooses to implement his answer also view the question I have submitted here:
表观IO.Ports.C# 中的串行端口缺陷或可能的硬件缺陷
推荐答案
你让自己太难了.只需将 SerialPort.NewLine 属性更改为>".并使用 SerialPort.ReadLine() 读取响应.如果需要，您仍然可以使用超时，分配 SerialPort.ReadTimeout 属性并准备捕获 TimeoutException.
You are making it too difficult on yourself. Simply change the SerialPort.NewLine property to ">". And use SerialPort.ReadLine() to read the response. You can still use a timeout if you need it, assign the SerialPort.ReadTimeout property and be prepared to catch the TimeoutException.
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