public async void RequestToGetInputReport()
{
const Int32 readTimeout = 5000;
String byteValue = null;
Byte[] inputReportBuffer = null;
Boolean success = false;
// If the device hasn't been detected, was removed, or timed out on a previous attempt
// to access it, look for the device.
if (!_deviceHandleObtained)
{
_deviceHandleObtained = FindTheHid();
}
if (_deviceHandleObtained)
{
// Don't attempt to exchange reports if valid handles aren't available
// (as for a mouse or keyboard under Windows 2000 and later.)
if (!_hidHandle.IsInvalid)
{
// Read an Input report.
// Don't attempt to send an Input report if the HID has no Input report.
// (The HID spec requires all HIDs to have an interrupt IN endpoint,
// which suggests that all HIDs must support Input reports.)
if (_myHid.Capabilities.InputReportByteLength > 0)
{
// Set the size of the Input report buffer.
inputReportBuffer = new Byte[_myHid.Capabilities.InputReportByteLength];
if (_transferType.Equals(TransferTypes.Control))
{
{
_transferInProgress = true;
// Read a report using a control transfer.
success = _myHid.GetInputReportViaControlTransfer(_hidHandle, ref inputReportBuffer);
_transferInProgress = false;
}
}
else
{
{
_transferInProgress = true;
// Read a report using interrupt transfers.
// Timeout if no report available.
// To enable reading a report without blocking the calling thread, uses Filestream's ReadAsync method.
// Create a delegate to execute on a timeout.
Action onReadTimeoutAction = OnReadTimeout;
// The CancellationTokenSource specifies the timeout value and the action to take on a timeout.
var cts = new CancellationTokenSource();
// Cancel the read if it hasn't completed after a timeout.
cts.CancelAfter(readTimeout);
// Specify the function to call on a timeout.
cts.Token.Register(onReadTimeoutAction);
// Stops waiting when data is available or on timeout:
Int32 bytesRead = await _myHid.GetInputReportViaInterruptTransfer(_deviceData, inputReportBuffer, cts);
// Arrive here only if the operation completed.
// Dispose to stop the timeout timer.
cts.Dispose();
_transferInProgress = false;
if (bytesRead > 0)
{
success = true;
}
}
}
}
}
if (!success)
{
CloseCommunications();
}
}
}
