Question

我从串口接收数据有问题。每次发送12个字节，我想读取每个字节并将它们放入一个数组中，然后在richtextbox中显示它们（每个字节将显示在一个单独的行中）。但是有一个问题：当连续发送数据时，我会得到一些额外的0，它们根本不相关，而且我在终端程序中没有收到。这是我的代码，如果你能帮助我，我感激不尽。

 private void data_received(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
    {
       richTextBox1.Invoke(new EventHandler(ReadFromPort));
    }

    private void ReadFromPort(object sender, EventArgs e)
    {
        int bytes = 0;
        label2.Text = "";
        bytes = serialPort1.BytesToRead;
        label2.Text = bytes.ToString();
        byte[] buffer = new byte[12];

        for (int k = 0; k < bytes; k++)
        {
            buffer[k] = 0;
        }
        serialPort1.Read(buffer, 0, bytes);
        for (int i = 0; i < buffer.Length  ; i++)
        {
            richTextBox1.AppendText(buffer[i].ToString() + Environment.NewLine);
        }

}

Answer 1

SerialPort.Read int bytesRead = serialPort1.Read(buffer, 0, bytes); for (int i = 0; i < bytesRead; i++) { … }，显然：

如果count大于输入缓冲区中的字节数，则读取的字节数减少。

返回值表示从端口实际读取的数据量。然后只显示数组中的这个字节数：

var ua = 'Mozilla/5.0 (iPad; CPU OS 9_1 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Version/9.0 Mobile/13B143 Safari/601.1'
var casper = require('casper').create({
    viewportSize: {width: 768, height: 1024},
    userAgent: ua
});
var login = {email: 'fakeemail@gmail.com', pw: 'fakepw'}
var usrObj = {
    succ: {},
    err: []
};

//exit function
function exit() {
    setTimeout(function() {
        casper.exit();
        casper.bypass(1);
    }, 10);
}
//success & error message function
function message(dat) {
    if (dat === 'credentials') {
        console.log('Error: Login credentials are missing');
        return exit();
    }
    else if (dat) {
        console.log(dat);
        return exit();
    }

    if (usrObj['err'].length > 0) {
        console.log('Error not empty...');
        console.log(usrObj.err);
        return exit();
    }
    else if (usrObj['succ']) {
        console.log('Success not empty...');
        console.log(JSON.stringify(usrObj.succ));
        return exit();
    }

}

//trim login credentials
login.email = login.email.trim();
login.pw = login.pw.trim();

if (login.email && login.pw) {

    casper.start('https://vimeo.com/log_in');
    casper.waitForSelector('form#login_form',
        function success() {
            this.echo(this.getCurrentUrl());
            this.sendKeys('form#login_form input[name="email"]', login.email);
            this.sendKeys('form#login_form input[name="password"]', login.pw);
            this.click('form#login_form input[type=submit][value="Log in with email"]');
        },
        function fail() {
            message('Error with Vimeo [page not loading]')
        }
    );
    casper.waitForSelector('#page_header>h1>a',
        function success() {
            this.echo(this.getCurrentUrl()); 
            usrObj['succ']['uname'] = this.getHTML('span.topnav_user_name');
            usrObj['succ']['profile'] = this.getElementAttribute('li.topnav_user_profile>a', 'href');
            var test = [];
            if (!usrObj.succ.uname) {test.push('Username not retrieved')}
            if (!usrObj.succ.profile) {test.push('Profile link not retrieved')}
            if (test.length > 0) {message(test.join('<br />'));}
            //else {message();}
        }, 
        function fail() {
            message('Login not successful');
        }
    ); 
    casper.thenOpen('https://vimeo.com/staceydavidgearz', 
        function success() {
            this.echo('Stacey David Profile: ' + this.getTitle());
            this.echo(this.getCurrentUrl()); 
            var finish = function() {
                usrObj['succ']['foll'] = true;
                message();
            }
            //var foll = this.getHTML('button[data-fatal-attraction="container:profile_page|component:follow"] > span');
            var foll = this.getElementAttribute('button[data-fatal-attraction="container:profile_page|component:follow"] > svg', 'viewBox');
            if (foll === '0 0 10 10') {
                this.click('button[data-fatal-attraction="container:profile_page|component:follow"]');
                setTimeout(function() {
                    foll = this.getElementAttribute('button[data-fatal-attraction="container:profile_page|component:follow"] > svg', 'viewBox');
                    if (foll === '0 0 10 10') {
                        message('Can\'t follow SD');

                    }
                    else {finish();}
                }, 250);
            }
            else {
                finish();
            }
        },
        function fail() {
            message('Not going to Stacey David profile page.');
        }
    );

    casper.run();
}
else {message('credentials');}

Answer 2

您正在将N个字节读入缓冲区，但显示整个缓冲区而不管您读入的字节数。有时你不会得到12个字节，但更少。但你仍然显示所有12个。

将for (int i = 0; i < buffer.Length ; i++)更改为for (int i = 0; i < bytes ; i++)

c＃中的额外和错误串行接收数据

2 个答案: