C# SerialPort DataReceived Event

本文关键字：Event DataReceived SerialPort | 更新日期: 2023-09-27 18:15:39

我正在监听串行端口的5字节信息。这5个字节是投票的完整答案所需的。我的代码监听serialport data_received事件并检查testoread。有时，事件会触发，bytesToRead为0。事件不是只有当数据可用时才会触发吗?

public SerialPort wheel = new SerialPort();
public void wheel_DataReceived(object sender, EventArgs e)
{
    if (wheel.BytesToRead < 5)
    {
        wheelRetry += 1;
        Log("Wheel Data Received: " + wheel.BytesToRead.ToString() + 
            " bytes. Need 5 bytes. Attempt #: " + wheelRetry.ToString());
    }

C# SerialPort DataReceived Event

您可以设置ReceivedBytesThreshold属性:

var port = new SerialPort();
port.Open();    
//Only raise the event if 5 bytes have been received
port.ReceivedBytesThreshold = 5;
port.DataReceived += (s, e) =>
{
    //Handle the data
};

请注意，您应该在打开端口后连接事件处理程序，
这是为了防止某些平台上的已知问题阻止事件

如果在打开端口之前已连接，则引发。

根据SerialPort.cs的参考源，是的，DataReceived事件可以在BytesToRead为0时触发，如果内部流的DataRecieved事件被触发并且事件参数具有EventType == SerialData.Eof。如果是这种情况，则不考虑BytesToRead的大小。

内部流的DataReceived事件处理程序CatchReceivedEvents的相关片段:

bool raiseEvent = false;
try {
    raiseEvent = stream.IsOpen && (SerialData.Eof == e.EventType || BytesToRead >= receivedBytesThreshold);    
}
catch {
    // Ignore and continue. SerialPort might have been closed already! 
}
finally {
    if (raiseEvent)
        eventHandler(this, e);  // here, do your reading, etc. 
}

您可以像@elgonzo建议的那样修改您的事件处理程序，以便您可以检查EventType:

public void wheel_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    if(e.EventType == SerialData.Eof) //return? possibly nothing to read
...
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