/// <summary>
/// Fires the barcode scanned event.
/// </summary>
/// <param name="deviceInfo">information about the device that generated
/// the barcode</param>
private void FireBarcodeScanned(BarcodeScannerDeviceInfo deviceInfo)
{
string barcode;
EventHandler handler;
barcode = this.keystrokeBuffer.ToString();
handler = this.BarcodeScanned;
this.keystrokeBuffer = new StringBuilder();
if (handler != null)
{
handler(this, new BarcodeScannedEventArgs(barcode, deviceInfo));
}
}
/// <summary>
/// Initializes a new instance of the BarcodeScannedEventArgs class.
/// </summary>
/// <param name="barcode">the barcode that was scanned</param>
/// <param name="deviceInfo">information about the device that sent the
/// barcode</param>
/// <exception cref="ArgumentNullException">if the barcode or deviceInfo are
/// null</exception>
public BarcodeScannedEventArgs(string barcode, BarcodeScannerDeviceInfo deviceInfo)
{
if (barcode == null)
{
throw new ArgumentNullException("barcode");
}
if (deviceInfo == null)
{
throw new ArgumentNullException("deviceInfo");
}
this.Barcode = barcode;
this.DeviceInfo = deviceInfo;
}
/// <summary>
/// Enumerates devices provided by GetRawInputDeviceList. We'll only listen
/// to these devices.
/// </summary>
/// <exception cref="ConfigurationErrorsException">if an error occurs
/// during configuration</exception>
private void InitializeBarcodeScannerDeviceHandles()
{
HardwareConfigurationSection config;
HardwareConfigurationElementCollection hardwareIdsConfig;
List <string> hardwareIds;
uint numDevices;
uint size;
config = HardwareConfigurationSection.GetConfiguration();
hardwareIdsConfig = config.HardwareIds;
hardwareIds = new List <string>();
numDevices = 0;
size = (uint)Marshal.SizeOf(typeof(NativeMethods.RAWINPUTDEVICELIST));
foreach (HardwareConfigurationElement hardwareId in hardwareIdsConfig)
{
hardwareIds.Add(hardwareId.Id);
}
// First, we get the number of raw input devices in the list by passing
// in IntPtr.Zero. Then we allocate sufficient memory and retrieve the
// entire list.
if (NativeMethods.GetRawInputDeviceList(IntPtr.Zero, ref numDevices, size) == 0)
{
IntPtr rawInputDeviceList;
rawInputDeviceList = Marshal.AllocHGlobal((int)(size * numDevices));
if (NativeMethods.GetRawInputDeviceList(
rawInputDeviceList,
ref numDevices,
size) != uint.MaxValue)
{
// Next, we iterate through the list, discarding undesired items
// and retrieving further information on the barcode scanner devices
for (int i = 0; i < numDevices; ++i)
{
uint pcbSize;
NativeMethods.RAWINPUTDEVICELIST rid;
pcbSize = 0;
rid = (NativeMethods.RAWINPUTDEVICELIST)Marshal.PtrToStructure(
new IntPtr((rawInputDeviceList.ToInt32() + (size * i))),
typeof(NativeMethods.RAWINPUTDEVICELIST));
if (NativeMethods.GetRawInputDeviceInfo(
rid.hDevice,
NativeMethods.RawInputDeviceInfoCommand.RIDI_DEVICENAME,
IntPtr.Zero,
ref pcbSize) >= 0)
{
if (pcbSize > 0)
{
string deviceName;
string friendlyName;
BarcodeScannerDeviceInfo info;
IntPtr data;
data = Marshal.AllocHGlobal((int)pcbSize);
if (NativeMethods.GetRawInputDeviceInfo(
rid.hDevice,
NativeMethods.RawInputDeviceInfoCommand.RIDI_DEVICENAME,
data,
ref pcbSize) >= 0)
{
deviceName = (string)Marshal.PtrToStringAnsi(data);
if ((from hardwareId in hardwareIds
where deviceName.Contains(hardwareId)
select hardwareId).Count() > 0)
{
friendlyName = GetDeviceFriendlyName(deviceName);
info = new BarcodeScannerDeviceInfo(
deviceName,
GetBarcodeScannerDeviceType(rid.dwType),
rid.hDevice,
friendlyName);
this.devices.Add(rid.hDevice, info);
}
}
Marshal.FreeHGlobal(data);
}
}
}
}
Marshal.FreeHGlobal(rawInputDeviceList);
}
}