停止 Stream.BeginRead()

Question

我需要从我的虚拟 com 端口读取数据并检测消息“Dreq”。一旦我按下连接按钮，它就会连接到我的 COM8 端口并开始读取新线程。我还有一个断开连接按钮，我希望在其中关闭读数并断开与 COM8 端口的连接。但是，我在关闭 BeginRead 时遇到问题。

public partial class Form1 : Form
{
    SerialPort sp;
    Stream stream;
    IAsyncResult recv_result;

    private void button1_Click(object sender, EventArgs e)
    {
        sp = new SerialPort("COM8", 9600);
        sp.Open();
        sp.ReadTimeout = 50000;
        sp.NewLine = "\n\r\0";
        stream = sp.BaseStream;
        recv_result = stream.BeginRead(new byte[1], 0, 0, new 
                                       AsyncCallback(ReadCallBack), stream);
    }

    private void ReadCallBack(IAsyncResult ar)
    {            
        Stream stream = (Stream)ar.AsyncState;
        string temp;

        while (stream.CanRead)
        {
            temp = sp.ReadLine();                
            // ... do something with temp
        }
    }

    private void disconnectButton_Click(object sender, EventArgs e)
    {
        stream.EndRead(recv_result);
        sp.Close();
    }
}

Answer 1

你可以尝试打电话sp.DiscardOutBuffer()。它将调用您的读取回调，然后您可以使用stream.EndRead().

private void disconnectButton_Click(object sender, EventArgs e)
{
    sp.DiscardOutBuffer();
    stream.EndRead(recv_result);
    sp.Close();
}