/// <summary>
/// Call HID functions that use Win32 API functions to locate a HID-class device
/// by its Vendor ID and Product ID. Open a handle to the device.
/// </summary>
///
/// <returns>
/// True if the device is detected, False if not detected.
/// </returns>
private Boolean FindTheHid()
{
var devicePathName = new String[128];
String myDevicePathName = "";
try
{
_deviceHandleObtained = false;
CloseCommunications();
_myVendorId = 0x16c0;
_myProductId = 0x05df;
// Get the HID-class GUID.
Guid hidGuid = _myHid.GetHidGuid();
// Fill an array with the device path names of all attached HIDs.
Boolean availableHids = _myDeviceManagement.FindDeviceFromGuid(hidGuid, ref devicePathName);
// If there is at least one HID, attempt to read the Vendor ID and Product ID
// of each device until there is a match or all devices have been examined.
if (availableHids)
{
Int32 memberIndex = 0;
do
{
// Open the handle without read/write access to enable getting information about any HID, even system keyboards and mice.
_hidHandle = _myHid.OpenHandle(devicePathName[memberIndex], false);
if (!_hidHandle.IsInvalid)
{
// The returned handle is valid,
// so find out if this is the device we're looking for.
//_myHid.DeviceAttributes.Size = Marshal.SizeOf(_myHid.DeviceAttributes);
Boolean success = _myHid.GetAttributes(_hidHandle, ref _myHid.DeviceAttributes);
if (success)
{
//Debug.WriteLine(" HIDD_ATTRIBUTES structure filled without error.");
//Debug.WriteLine(" Structure size: " + _myHid.DeviceAttributes.Size);
//Debug.WriteLine(" Vendor ID: " + Convert.ToString(_myHid.DeviceAttributes.VendorID, 16));
//Debug.WriteLine(" Product ID: " + Convert.ToString(_myHid.DeviceAttributes.ProductID, 16));
//Debug.WriteLine(" Version Number: " + Convert.ToString(_myHid.DeviceAttributes.VersionNumber, 16));
if ((_myHid.DeviceAttributes.VendorID == _myVendorId) && (_myHid.DeviceAttributes.ProductID == _myProductId))
{
//Debug.WriteLine(" Handle obtained to my device");
// Display the information in form's list box.
//InfoBox.Text += "\nHandle obtained to my device:";
InfoBox.Text = " VID=" + Convert.ToString(_myHid.DeviceAttributes.VendorID, 16);
InfoBox.Text += " PID=" + Convert.ToString(_myHid.DeviceAttributes.ProductID, 16);
_deviceHandleObtained = true;
myDevicePathName = devicePathName[memberIndex];
}
else
{
// It's not a match, so close the handle.
_deviceHandleObtained = false;
_hidHandle.Close();
}
}
else
{
// There was a problem retrieving the information.
//Debug.WriteLine(" Error in filling HIDD_ATTRIBUTES structure.");
_deviceHandleObtained = false;
_hidHandle.Close();
}
}
// Keep looking until we find the device or there are no devices left to examine.
memberIndex = memberIndex + 1;
}while (!((_deviceHandleObtained || (memberIndex == devicePathName.Length))));
}
if (_deviceHandleObtained)
{
// The device was detected.
// Learn the capabilities of the device.
_myHid.Capabilities = _myHid.GetDeviceCapabilities(_hidHandle);
// Find out if the device is a system mouse or keyboard.
_hidUsage = _myHid.GetHidUsage(_myHid.Capabilities);
//Close the handle and reopen it with read/write access.
_hidHandle.Close();
_hidHandle = _myHid.OpenHandle(myDevicePathName, true);
if (_hidHandle.IsInvalid)
{
InfoBox.Text += "The device is a system " + _hidUsage + ".";
}
else
{
if (_myHid.Capabilities.InputReportByteLength > 0)
{
// Set the size of the Input report buffer.
var inputReportBuffer = new Byte[_myHid.Capabilities.InputReportByteLength];
_deviceData = new FileStream(_hidHandle, FileAccess.Read | FileAccess.Write, inputReportBuffer.Length, false);
inputReportBuf = new Byte[_myHid.Capabilities.InputReportByteLength];
}
if (_myHid.Capabilities.OutputReportByteLength > 0)
{
Byte[] outputReportBuffer = null;
}
// Flush any waiting reports in the input buffer. (optional)
_myHid.FlushQueue(_hidHandle);
}
ErrorBox.Text = "";
}
else
{
ErrorBox.Text = "Device not found.";
}
return(_deviceHandleObtained);
}
catch (Exception ex)
{
DisplayException(Name, ex);
throw;
}
}