Obtaining Device Path of USB Device PInvoke

Question

4.00/5 (1 vote)

See more:

Hi, I am working with the setupapi.dll in order to control a USB device.

I am calling the SetupDiGetDeviceInterfaceDetail function to obtain the device path, of my USB device. The function is called successfully however the device path returns as "/". here is the code That I am using. I suspect that has to do something with the formatting of the native method. Here is the Link to the PInvoke method.

C#

 [StructLayout(LayoutKind.Sequential)]
  public struct SP_DEVICE_INTERFACE_DETAIL_DATA // user made struct to store device path
      {
            public UInt32 cbSize;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string DevicePath;
      }

  [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
  public static extern Boolean SetupDiGetDeviceInterfaceDetail(IntPtr hDevInfo, ref SP_DEVICE_INTERFACE_DATA deviceInterfaceData, ref SP_DEVICE_INTERFACE_DETAIL_DATA deviceInterfaceDetailData, 
            UInt32 deviceInterfaceDetailDataSize, out UInt32 requiredSize, ref SP_DEVINFO_DATA deviceInfoData);


public List<string> GetDetailsDeviceInterface()
        {
            try
            {
                UInt32 nBytes = 256;
                UInt32 nRequiredSize;
                List<string> DetailsList = new List<string>();
                if (SetupAPICalls.SetupDiGetDeviceInterfaceDetail(info, ref DeviceData, ref DetailData, nBytes, out nRequiredSize, ref DeviceInfo));
                {
                    UInt32 reg_type;
                    IntPtr ptrBuf = new IntPtr();
                    ptrBuf = Marshal.AllocHGlobal((int)BUFFER_SIZE);
                    Debug.WriteLine("Device Path: "+DetailData.DevicePath);
                    DetailsList.Add(DetailData.DevicePath);
                    if (SetupAPICalls.SetupDiGetDeviceRegistryProperty(info, ref DeviceInfo, 0x00000000, out reg_type, ptrBuf, nBytes, out nRequiredSize))
                    {
                        string ControllerDeviceDesc = Marshal.PtrToStringAuto(ptrBuf);
                        Debug.WriteLine("Device description: " + ControllerDeviceDesc);
                        DetailsList.Add(ControllerDeviceDesc);
                        return DetailsList;
                    }
                    else
                    {
                        throw new Exception("DfuSe: Unable to obtain Device description: " + new Win32Exception(Marshal.GetLastWin32Error()).Message);              
                    }
                }
                throw new Exception("DfuSe: Unable to obtain Device Info, please Connect device: "+new Win32Exception(Marshal.GetLastWin32Error()).Message);              
            }
            catch(Win32Exception ex)
            {
                throw ex;
            }

        }

Thanks in anticipation.

Posted 4-Jun-12 9:09am

nanomass

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

nanomass · Accepted Answer · 2012-06-04T10:08:00

Ok I found what my mistake was, problem was that I forgot to place the CharSet, property to auto when I created the struct.

I had:

C#

[StructLayout(LayoutKind.Sequential)]
  public struct SP_DEVICE_INTERFACE_DETAIL_DATA // user made struct to store device path
      {
            public UInt32 cbSize;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string DevicePath;
      }

When It should have been

C#

[StructLayout(LayoutKind.Sequential), CharSet = CharSet.Auto]
  public struct SP_DEVICE_INTERFACE_DETAIL_DATA // user made struct to store device path
      {
            public UInt32 cbSize;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string DevicePath;
      }

Hope this can help someone in the future.