我遇到一个小型C＃应用程序的问题。 应用程序必须通过串行端口连接到读取Data Matrix代码的条形码扫描器。 Data Matrix代码表示一个zip存档的字节数组。我读了很多关于SerialPort.DataReceived的工作方式，但我无法找到解决问题的优雅方案。应用程序应该使用不同的条形码扫描仪，所以我不能使它具有扫描仪特定。以下是我的一些代码：
using System;
using System.IO;
using System.IO.Ports;
using System.Windows.Forms;
using Ionic.Zip;
namespace SIUI_PE
{
public partial class Form1 : Form
{
SerialPort _serialPort;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
try
{
_serialPort = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
}
catch (Exception ex)
{
MessageBox.Show("Error:" + ex.ToString());
return;
}
_serialPort.Handshake = Handshake.None;
_serialPort.ReadBufferSize = 10000;
_serialPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived);
_serialPort.Open();
}
void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
byte[] data = new byte[10000];
_serialPort.Read(data, 0, 10000);
File.WriteAllBytes(Directory.GetCurrentDirectory() + "/temp/fis.zip", data);
try
{
using (ZipFile zip = ZipFile.Read(Directory.GetCurrentDirectory() + "/temp/fis.zip"))
{
foreach (ZipEntry ZE in zip)
{
ZE.Extract(Directory.GetCurrentDirectory() + "/temp");
}
}
File.Delete(Directory.GetCurrentDirectory() + "/temp/fis.zip");
}
catch (Exception ex1)
{
MessageBox.Show("Corrupt Archive: " + ex1.ToString());
}
}
}
}
所以我的问题是：我怎么知道我读了扫描仪发送的所有字节？
答案 0 :(得分：1)
我阅读条形码数据的代码已经在生产中完美运行了好几年看起来像这样：
注意，我的应用程序必须读取标准UPC条形码以及GS1 DataBar，因此您可能不需要一些代码......
这方面的关键是：
string ScanData = ScannerPort.ReadExisting();
，可在DoScan部分找到，只是将扫描数据作为字符串读取。它绕过了知道发送了多少字节的需要，并使代码的其余部分更容易处理。
// This snippet is in the Form_Load event, and it initializes teh scanner
InitializeScanner();
ScannerPort.ReadExisting();
System.Threading.Thread.Sleep(1000);
// ens snippet from Form_Load.
this.ScannerPort.DataReceived += new SerialDataReceivedEventHandler(ScannerPort_DataReceived);
delegate void DoScanCallback(); // used for updating the form UI
void DoScan()
{
if (this.txtCouponCount.InvokeRequired)
{
DoScanCallback d = new DoScanCallback(DoScan);
this.Invoke(d);
return;
}
System.Threading.Thread.Sleep(100);
string ScanData = ScannerPort.ReadExisting();
if (isInScanMode)
{
try
{
HandleScanData(ScanData);
}
catch (Exception ex)
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show("Invalid Scan");
}
}
}
void ScannerPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
// this call to sleep allows the scanner to receive the entire scan.
// without this sleep, we've found that we get only a partial scan.
try
{
DoScan();
}
catch (Exception ex)
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show("Unable to handle scan event in ScannerPort_DataReceived." + System.Environment.NewLine + ex.ToString());
}
}
void Port_ErrorReceived(object sender, System.IO.Ports.SerialErrorReceivedEventArgs e)
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show(e.EventType.ToString());
}
private void HandleScanData(string ScanData)
{
//MessageBox.Show(ScanData + System.Environment.NewLine + ScanData.Length.ToString());
//Determine which type of barcode has been scanned, and handle appropriately.
if (ScanData.StartsWith("A") && ScanData.Length == 14)
{
try
{
ProcessUpcCoupon(ScanData);
}
catch (Exception ex)
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show("Unable to process UPC coupon data" + System.Environment.NewLine + ex.ToString());
}
}
else if (ScanData.StartsWith("8110"))
{
try
{
ProcessDataBarCoupon(ScanData);
}
catch (Exception ex)
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show("Unable to process DataBar coupon data" + System.Environment.NewLine + ex.ToString());
}
}
else
{
System.Media.SystemSounds.Beep.Play();
MessageBox.Show("Invalid Scan" + System.Environment.NewLine + ScanData);
}
}
private void InitializeScanner()
{
try
{
ScannerPort.PortName = Properties.Settings.Default.ScannerPort;
ScannerPort.ReadBufferSize = Properties.Settings.Default.ScannerReadBufferSize;
ScannerPort.Open();
ScannerPort.BaudRate = Properties.Settings.Default.ScannerBaudRate;
ScannerPort.DataBits = Properties.Settings.Default.ScannerDataBit;
ScannerPort.StopBits = Properties.Settings.Default.ScannerStopBit;
ScannerPort.Parity = Properties.Settings.Default.ScannerParity;
ScannerPort.ReadTimeout = Properties.Settings.Default.ScannerReadTimeout;
ScannerPort.DtrEnable = Properties.Settings.Default.ScannerDtrEnable;
ScannerPort.RtsEnable = Properties.Settings.Default.ScannerRtsEnable;
}
catch (Exception ex)
{
MessageBox.Show("Unable to initialize scanner. The error message received will be shown next. You should close this program and try again. If the problem persists, please contact support.", "Error initializing scanner");
MessageBox.Show(ex.Message);
Application.Exit();
}
}
答案 1 :(得分：0)
如SerialPort.DataReceived的文档中所述，“使用BytesToRead属性来确定在缓冲区中剩余的数据量。”
这是SerialPort.BytesToRead
的文档http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.bytestoread.aspx