/// <summary>
/// Initialises the device
/// </summary>
/// <param name="strPath">Path to the device</param>
private void Initialise(string strPath)
{
// Create the file from the device path
m_hHandle = CreateFile(strPath, GENERIC_READ | GENERIC_WRITE, 0, IntPtr.Zero, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, IntPtr.Zero);
if (m_hHandle != InvalidHandleValue || m_hHandle == null) // if the open worked...
{
IntPtr lpData;
if (HidD_GetPreparsedData(m_hHandle, out lpData)) // get windows to read the device data into an internal buffer
{
try
{
HidCaps oCaps;
HidP_GetCaps(lpData, out oCaps); // extract the device capabilities from the internal buffer
m_nInputReportLength = oCaps.InputReportByteLength; // get the input...
m_nOutputReportLength = oCaps.OutputReportByteLength; // ... and output report lengths
//m_oFile = new FileStream(m_hHandle, FileAccess.Read | FileAccess.Write, true, m_nInputReportLength, true);
m_oFile = new FileStream(new SafeFileHandle(m_hHandle, false), FileAccess.Read | FileAccess.Write, m_nInputReportLength, true);
BeginAsyncRead(); // kick off the first asynchronous read
}
catch (Exception ex)
{
throw HIDDeviceException.GenerateWithWinError("Failed to get the detailed data from the hid.");
}
finally
{
HidD_FreePreparsedData(ref lpData); // before we quit the funtion, we must free the internal buffer reserved in GetPreparsedData
}
}
else // GetPreparsedData failed? Chuck an exception
{
throw HIDDeviceException.GenerateWithWinError("GetPreparsedData failed");
}
}
else // File open failed? Chuck an exception
{
m_hHandle = IntPtr.Zero;
throw HIDDeviceException.GenerateWithWinError("Failed to create device file");
}
}
/// <summary>
/// Finds a device given its PID and VID
/// </summary>
/// <param name="nVid">Vendor id for device (VID)</param>
/// <param name="nPid">Product id for device (PID)</param>
/// <param name="oType">Type of device class to create</param>
/// <returns>A new device class of the given type or null</returns>
public static HIDDevice FindDevice(int nVid, int nPid, Type oType)
{
string strPath = string.Empty;
string strSearch = string.Format("vid_{0:x4}&pid_{1:x4}", nVid, nPid); // first, build the path search string
Guid gHid = HIDGuid;
//HidD_GetHidGuid(out gHid); // next, get the GUID from Windows that it uses to represent the HID USB interface
IntPtr hInfoSet = SetupDiGetClassDevs(ref gHid, IntPtr.Zero, IntPtr.Zero, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE); // this gets a list of all HID devices currently connected to the computer (InfoSet)
try
{
DeviceInterfaceData oInterface = new DeviceInterfaceData(); // build up a device interface data block
oInterface.Size = Marshal.SizeOf(oInterface);
// Now iterate through the InfoSet memory block assigned within Windows in the call to SetupDiGetClassDevs
// to get device details for each device connected
int nIndex = 0;
//bool result = SetupDiEnumDeviceInterfaces(hInfoSet, 0, ref gHid, (uint)nIndex, ref oInterface);
while (SetupDiEnumDeviceInterfaces(hInfoSet, 0, ref gHid, (uint)nIndex, ref oInterface)) // this gets the device interface information for a device at index 'nIndex' in the memory block
{
string strDevicePath = GetDevicePath(hInfoSet, ref oInterface); // get the device path (see helper method 'GetDevicePath')
if (strDevicePath.IndexOf(strSearch) >= 0) // do a string search, if we find the VID/PID string then we found our device!
{
HIDDevice oNewDevice = (HIDDevice)Activator.CreateInstance(oType); // create an instance of the class for this device
oNewDevice.Initialise(strDevicePath); // initialise it with the device path
return(oNewDevice); // and return it
}
nIndex++; // if we get here, we didn't find our device. So move on to the next one.
}
}
catch (Exception ex)
{
throw HIDDeviceException.GenerateError(ex.ToString());
//Console.WriteLine(ex.ToString());
}
finally
{
// Before we go, we have to free up the InfoSet memory reserved by SetupDiGetClassDevs
SetupDiDestroyDeviceInfoList(hInfoSet);
}
return(null); // oops, didn't find our device
}
