C# Serial.DataRecieved data is in pieces

问题

I'm making a program that is searching all available COM ports for a text "ConnectAlready." Thanks to the help of people on stack overflow I was able to do a majority of it. I print the data i receive on the console, but instead of getting one string "ConnectAlready", i get something like:

Conne
ct
alre
ady

Each one of those is a different string, and therefore i cannot check if the serial port is reading "ConnectAlready."

private void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {
        SerialPort serialPort1 = sender as SerialPort;
        byte[] data = new byte[serialPort1.BytesToRead];
        Stream portStream = serialPort1.BaseStream;
        portStream.Read(data, 0, data.Length); 
        string dataString = Encoding.UTF8.GetString(data);
        Console.WriteLine(dataString);
        bool hasData = dataString.Contains("ConnectAlready");
        if (hasData)
        {
            established = true;
            estport = serialPort1.PortName;
            MessageBox.Show(estport);
        }
    }

Any advice? thanks for your help!

回答1:

Okay, your problem is the following: If you receive data on your Port, the event fires. Then you read the bytes that are already there. But your computer is faster than your transmission --> Not the whole message is already in your buffer.

Here are two possible solutions:

1: If your Message contains a Newline-Character at the end you could do it easy like this:

//Add to your init:
YourSerialPort.Timeout = 100; //Maximum duration of your message in milliseconds
YourSerialPort.NewLine = "\r\n"; //You can also change the newline-character (you can also omit)

private void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    string dataString = ((SerialPort)sender).ReadLine();
    if (dataString.Contains("ConnectAlready"))
    {
        //Your code
    }
}

If you use the Arduino Serial.println()-function, this would be your solution.

2: Wait a short time before read your message:

private void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    Thread.sleep(50);
    SerialPort serialPort1 = sender as SerialPort;
    byte[] data = new byte[serialPort1.BytesToRead];
    Stream portStream = serialPort1.BaseStream;
    portStream.Read(data, 0, data.Length); 
    string dataString = Encoding.UTF8.GetString(data);
    Console.WriteLine(dataString);
    bool hasData = dataString.Contains("ConnectAlready");
    if (hasData)
    {
        //Your code
    }
}

Good luck!

来源：https://stackoverflow.com/questions/34698237/c-sharp-serial-datarecieved-data-is-in-pieces