Question

C#Datareceived问题

这是我根据网上编写的串口接收数据的程序片段，为什么接收不了呢。我设置断点逐步运行后，为什么不运行 void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e) 方法呢？
private void button2_Click(object sender, EventArgs e)
{
//接收串口数据
if (isOpen)
{
try
{
//sp.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(sp_DataReceived);
//sp.DataReceived+=new SerialDataReceivedEventHandler(sp_DataReceived);
//txtRecvData.Text = sp.ReadLine() ;
sp.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived);
}
catch (Exception)
{
MessageBox.Show("读取串口数据错误");
return;
}
}
else
{
MessageBox.Show("串口未打开");
return;
}

}

void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
string a;
a = sp.ReadExisting();
MessageBox.Show(a);
}

Answer 1

　　注意ReceivedBytesThreshold属性，默认值是1，表示接收缓冲区每有一个字节就促发 DataReceived事件。如果该属性数值过大，那边缓冲区的字节数需达到这个值才会促发DataReceived事件。
　　如果串口打开并且确认另一端串口已发送数据。且ReceivedBytesThreshold为合理的值。就会促发DataReceived事件。
　　如有疑问，继续追问。

Answer 2

试试先监听事件，再调用串口的Open