A USB HID Component for C#

I have created my own circuit using 5V leds and I have conected it to my PC using an USB 2.0 connection, but I don't have any PID or VID to recognize my device.How can I send data to my device in this case?

Please help

Very helpful for my work

Hi,

I was read the code and do a little modifications on that.

But I have a problem that is every time when I called CheckDevicePresent(), it seems cause the DataRecievedEventHandler called twice.

In other words to say,
If the code as follows::
...
usb.CheckDevicePresent();
usb.CheckDevicePresent();
usb.CheckDevicePresent();
...
then when every time data received, it will do OnDataReceived() three times....and so on..

so, how to prevent it happened?

I had the same problem, sort of. The usb_OnSpecifiedDeviceArrived was called twice at startup which subsequently led to (I think) several sending and receiving handlers being registered in CheckDevicePresent().

So I changed the code to this:

C#

if (specified_device != null)
              {
                  history = true;
              }
              else
              {
                  specified_device = SpecifiedDevice.FindSpecifiedDevice(this.vendor_id, this.product_id);    // look for the device on the USB bus

                  if (specified_device != null)   // did we find it?
                  {
                      if (OnSpecifiedDeviceArrived != null)
                      {
                          this.OnSpecifiedDeviceArrived(this, new EventArgs());
                          specified_device.DataRecieved += new DataRecievedEventHandler(OnDataRecieved);
                          specified_device.DataSend += new DataSendEventHandler(OnDataSend);
                      }
                  }
                  else
                  {
                      if (OnSpecifiedDeviceRemoved != null && history)
                      {
                          this.OnSpecifiedDeviceRemoved(this, new EventArgs());
                      }
                  }
              }

This solved my problem with multiple specified device arrived and send and receive events.

Support for multiple instances of the same device would be very nice! Smile | :)

Besides that, nice piece of software.

Regards
Thomas

I noticed that there have been some problems with that observed by others (as well). What I did to fix this problem was to add a FILE_FLAG_DELETE_ON_CLOSE flag to the CreateFile function call in the HIDDevice class.

And do the following:

//m_oFile.Close();

in the write method.

Hope this helps somebody.

Cheers.

modified on Thursday, July 1, 2010 1:21 AM

Nice work
Works fine
Thank you

Hi, I'm trying to use this library in a seperate class. Class should handle all communication from the main application to the USB via properties. I have some trouble to get the usb library events into this class. As this class (obviously) doesn't contain a form I can't drop the component on the form.. Smile | :)

I am a bit puzzled if and how I should handle below mentioned events (as they don't exists in a non-form class?)

protected override void OnHandleCreated(EventArgs e) and<br />
protected override void WndProc(ref Message m)

At the moment I have the below (simplified) skeleton in place, where I would like to get the behaviour that when the hardware isn't inserted the loop continues till the hardware is inserted. Unfortunately it doesn't work....I think I do something wrong with the eventhandlers.... Frown | :-(

Any hints appreciated...tnx Boris.

Main form:

public partial class FrmMain : Form
    {
        measClass myMeas;
        
        public FrmMain()
        {
            InitializeComponent();
            myMeas = new measClass();
        }
        private void FrmMain_Load(object sender, EventArgs e)
        {
            while (!myMeas.portopen)
            {
                if (MessageBox.Show("USB hardware not found, check USB connection", "Hardware Error", MessageBoxButtons.AbortRetryIgnore,               MessageBoxIcon.Error) == DialogResult.Abort)
                {
                    Environment.Exit(0);
                }
            }
            // do rest of the things, main applications starts
        }
     }

MeasClass in seperate .cs file.

public class measClass
        {
            UsbHidPort myUsb;
            public bool portopen = false;

            public measClass()
            {
                myUsb = new UsbHidPort();
                myUsb.OnSpecifiedDeviceRemoved += new System.EventHandler(this.usb_OnSpecifiedDeviceRemoved);
                myUsb.OnDeviceArrived += new System.EventHandler(this.usb_OnDeviceArrived);
                myUsb.OnDeviceRemoved += new System.EventHandler(this.usb_OnDeviceRemoved);
                myUsb.OnDataRecieved += new UsbLibrary.DataRecievedEventHandler(this.usb_OnDataRecieved);
                myUsb.OnDataSend += new System.EventHandler(this.usb_OnDataSend);
                myUsb.OnSpecifiedDeviceArrived += new System.EventHandler(this.usb_OnSpecifiedDeviceArrived);
                myUsb.VendorId = 0x4242;
                myUsb.ProductId = 0x0002;
                myUsb.CheckDevicePresent();
            }

            private void usb_OnSpecifiedDeviceArrived(object sender, EventArgs e)
            {
                portopen = true;
            }

            // same way all the other usb_on handlers.
        }

Hi Boris,

Were you ever able to solve the problem of putting the HID USB library of codeproject in a sperate class? I am very curious how you did this. Thanks Erik

(erik.haverkamp@gmail.com)

This application works great on Windows XP 32 bit. What do I need to do to get it to work on Windows 7 64-bit?

Have you received any feedback one your question regarding Window 7 64 bit. I have the same concerns. Thanks D

Unfortunately I did not get an answer. However, I started debugging a similar app with a Symbol barcode scanner on both windows platforms. I found the HID and VID values changed when used in Windows 7 vs Windows XP. Unfortunately, I didn't have time to look further into the issue but I wanted to share what I did find.

I was able to modify my version of the library to work on a Windows 7 64-bit machine.

in Win32Usb.cs, in the DeviceInterfaceData struct change 'public int Reserved' to a IntPtr
in HIDDevice.cs, in the GetDevicePath function change oDetail.Size = 5 to oDetail.Size = 8

These changes will only work on a 64-bit machine (not both).

Good luck.

So I needed to make this library work on both machines, without having to bundle a different dll. This seems to work:

Original line in file: Win32Usb.cs
public int Reserved;
replaced with:
public IntPtr Reserved;
(This seems to not affect 32 bit operation if left that way.)

In HIDDevice.cs, replace:

oDetail.Size = 5; // with long comment I also couldn't think of a better way of fixing

with:

DeviceInterfaceDetailData oDetail = new DeviceInterfaceDetailData();
if (Marshal.SizeOf(typeof(IntPtr)) == 8)
{
oDetail.Size = 8; //For 64 bit.
}
else
{
oDetail.Size = 5; // long comment
}

This seems to work for both systems, though we are still testing it.

Thanks, this is a great library! Now if I can find or make one as good for OSX!

This fix works great. Thanks for posting it!

I wanted to add one more thing to this fix, on win 7 x64 in VS2012 I had to do the steps above plus I had to set the application executable to "Prefer 32 bit" under properties -> build options.
Without that setting the method SetupDiEnumInterfaces would always fail with code 1781.

Here's your answer

I was using this great library with success but then noticed that when sending large amounts of data, I would randomly lose some percentage of the packets. Apparently me .NET program was not servicing the arriving data fast enough and the Windows ReadFile buffer was overflowing and throwing out the oldest reports.

Jan Axelson describes how to increase the default number of reports that Windows stores before overflowing:

*big* thanks to Jan and Wimar for making this info/code available!!!

http://www.lvr.com/hidfaq.htm

How large is the ReadFile buffer?

Under Windows 98 Gold, 2 reports. Under Windows 98 SE, Windows 2000 and Windows Me, the default is 8 reports. Under Windows XP, the default is 32 reports. Under all but Windows 98 Gold, you can change the defaults with HidD_SetNumInputBuffers. The maximum size under Windows XP and later is 512. The maximum size under Windows 2000 is 200. Use HidD_GetNumInputBuffers to read the buffer size.

How can I keep my application from losing reports?

If the ReadFile buffer is full, on receiving a new report, the driver drops the oldest report. To prevent losing reports, use HidD_SetNumInputBuffers to increase the buffer size, use longer reports sent less frequently, have the application read reports more often, or increase the size of the buffer in the call to ReadFile. (ReadFile returns as many reports as are available, up to ReadFile's buffer size.)

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Default is 32, max is 512 for WinXP

[DllImport("hid.dll", SetLastError = true)]
protected static extern Boolean HidD_GetNumInputBuffers(IntPtr HidDeviceObject, ref Int32 NumberBuffers);

[DllImport("hid.dll", SetLastError = true)]
protected static extern Boolean HidD_SetNumInputBuffers(IntPtr HidDeviceObject, Int32 NumberBuffers);

Could someone explain me how to use it?
I have Microsoft Visual C# 2008 and it converts it when first opening it.
I tried to make a new form and put the code in this website in it, but it doesn't work. It gives tons of errors.
Could someone explain me how to use it? Or make a complete project and upload it?
Thanks.

Hi,
i would use the library for a student project.
But cause of my OS (win7 64bit) the the library don't work correctly.
Where are any actually implementations of it?

I converted this thing over to a WPF component and have been testing it with a ATMEL Key.
After a few mods for WPF, the code works great, although I am still trying to absorb all of
wimars great coding.

This may be a dumb question but I'm perplexed by the following two lines of code in the
USBHidPort.cs file within the CheckDevicePresent() method:

specified_device.DataReceived += new DataReceivedEventHandler(OnDataReceived);
specified_device.DataSend += new DataSendEventHandler(OnDataSend);

I believe the code is attempting to bubble up the "DataReceived" event from the specified_device
object to UsbHidPort object so it can be piped out to your WPF or Forms App as a
"OnDataReceived" event.

It works, but I've never seen this syntax before. The code seems to be inserting an event itself
in where an event handler method belongs/goes. Evidently this syntax not only accepts an event
for an argument, but it will also fire it! Perplexed? Anybody have a link or reference that
explains why that works?

Thanks Greg.

It's attaching events to the newly found usb device so you can receive data and get confirmation on sends.

I'd call that standard event syntax since C# 1.1 at least.

Hi Greg,

I'm currently working on a WPF project using this library. I have everything working except the arrived and removed events. When you did this, how did you get these to fire? I imagine it has something to do with the code in the instructions:

protected override void OnHandleCreated(EventArgs e)
{
base.OnHandleCreated(e);
usb.RegisterHandle(Handle);
}
protected override void WndProc(ref Messagea m)
{
usb.ParseMessages(ref m);
base.WndProc(ref m); // pass message on to base form
}

Thanks,
Alex

-edit-
I answered my own question:

private void Window_Loaded(object sender, RoutedEventArgs e)
		{
			HwndSource source = HwndSource.FromHwnd((new System.Windows.Interop.WindowInteropHelper(this)).Handle);
			hidDevice.RegisterHandle((new System.Windows.Interop.WindowInteropHelper(this)).Handle);
			source.AddHook(new HwndSourceHook(WndProc));
		}

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
		{

			hidDevice.ParseMessages(msg, wParam);
			return IntPtr.Zero;
		}

and change ParseMessages in UsbHidPort to:

public void ParseMessages(int msg, IntPtr wParam)
		  {
			  if (msg == Win32Usb.WM_DEVICECHANGE)	// we got a device change message! A USB device was inserted or removed
			  {
				  switch (wParam.ToInt32())	// Check the W parameter to see if a device was inserted or removed
				  {
					  case Win32Usb.DEVICE_ARRIVAL:	// inserted
						  if (OnDeviceArrived != null)
						  {
							  OnDeviceArrived(this, new EventArgs());
							  CheckDevicePresent();
						  }
						  break;
					  case Win32Usb.DEVICE_REMOVECOMPLETE:	// removed
						  if (OnDeviceRemoved != null)
						  {
							  OnDeviceRemoved(this, new EventArgs());
							  CheckDevicePresent();
						  }
						  break;
				  }
			  }
		  }

modified on Wednesday, February 16, 2011 11:21 AM

I don't see a way of sending and receiving feature reports. Is this possible?

Is it possible to specify if the reads and writes are using control or interrupt transfers?

Is it possible to obtain a serial number from a device?

What good is the CheckDevicePresent Method if it doesn't return anything. The documentation lacks the necessary information to understand how this is useful...

Eblan

A USB HID Component for C#

Introduction

Background

Using the Code

Points of Interest

History

License

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