Error 1784 when invoke SetupDiGetDeviceInterfaceDetail() in C#

Question

//c# code: public class Win32 {...... [StructLayout(LayoutKind.Sequential CharSet=CharSet.Auto)] public struct SP_DEVICE_INTERFACE_DETAIL_DATA { public uint cbSize; public char* DevicePath; } [DllImport(setupapi.dll CharSet=CharSet.Auto)] [return: MarshalAs(UnmanagedType.Bool)] public static extern bool SetupDiGetDeviceInterfaceDetail( [In]IntPtr DeviceInfoSet [In] SP_DEVICE_INTERFACE_DATA *DeviceInterfaceData [Out]SP_DEVICE_INTERFACE_DETAIL_DATA *DeviceInterfaceDetailData [In]int DeviceInterfaceDetailDataSize [Out]int *RequiredSize [Out]SP_DEVINFO_DATA *DeviceInfoData ); ...... } public class usbdevice {...... ptrDeviceInterfaceDetailData = (Win32.SP_DEVICE_INTERFACE_DETAIL_DATA*)Win32.GlobalAlloc(Win32.GPTRnBytesRequired); ptrDeviceInterfaceDetailData->cbSize = (uint)sizeof(Win32.SP_DEVICE_INTERFACE_DETAIL_DATA); ptrDeviceInfoData->cbSize = Marshal.SizeOf( new Win32.SP_DEVINFO_DATA().GetType() ); bResult =Win32.SetupDiGetDeviceInterfaceDetail(hDevInfo ptrDeviceInterfaceData ptrDeviceInterfaceDetailData //[out] pointer to a buffer to store the interface detail data nBytesRequired // the buffer size null ptrDeviceInfoData); lasterror = Win32.GetLastError();// Error number:1784. How to settle this problem????

gongdehui · Answer

Hi! Bart Thank you very much! But my debug result do not agree with you.^_^The error 1784 stilll exits. You can see SetupDiGetDeviceInterfaceDetail() in MSDNand you can see what we to do with the parameter ptrDeviceInterfaceDetailData.And I suppose GlobalAlloc() can offer it a certain address. In your last letteryou said you can not get through my code.I am sorry that I am not a good program with good programming style.^_^ But I hope you can get it and then help me to finish the project.Sonow I hope I can give you some useful tips. 1below to the breakpoint 6the last one pls change Marshal.GetLastWin32Error() with Win32.GetLastError()then you can get the Error number 122not 8 any more.^_^This is the first thing. 2Herewe just care about the above problemerror 1784so you do not need to know other code which I not mention here later. At breakpoint 1method refreshalldevicespathes(temp) just return the devicepath of the U-disk of one usb which dbcc_name is temp.And we will pass the devicepath as a parameter to method Opendevice()(in Form1.cs) to open the very U-diskand then we can format this U-disk.Soat first we must get the U-disk's devicepath.The mothod refreshalldevicespathes(temp) invokes many other methodsbut all of them just cooperate to enumerate the U-disk's devicepath.And herewe do not need to care about the parameter tempand you can see that it never be used in later code.I will use it when we can enumerate the U-disk's devicepathand tell you what role it acts. 3At breakpoint 2 usbinfo = enum_usb(devicename); use method enum_usb we get the device infomation of the first instance of usb device class.And then we use the usbinfo to get the handle of the first child device of this usb device instance.dwStatus = Win32.CM_Get_Child(&diskDevInst usbDevInst 0 );And the fist child of this usb device instance is U-disk(flash maybe)(It's defined by the firmware of usb device).Because the U-disk belongs to DISK device classso we use enum_disk() to enumetate all the DISK device instance on the local machineand return the devicepath of the very U-disk whose diskdeviceinfo->DevInst equals to the first usb device instance's first child's handle childDevInst.^_^Let take mp3 for an examplea material mp3 is an instance of usb device classand the flash(or disk) inside is its first child devicewhich belongs to DISK device class.If one or more cards(such as MSFCetc.) can attach to this mp3then the card(s) is the second childthird childetc. of this mp3.But what we want to get is the devicepath of the first child(U-disk or flash). 4After you have done the 1 stepclick the debug buttonwhen it finish initializing th UIattach your mp3 to PCand then run to breakpoint 1step by stepyou can see how those methods enumate to the diskdeviceinfoand as you go to breakpoint 6you will get error number 122it's what we wantand nBytesRequired returns 244.The first time we invoke SetupDiGetDeviceInterfaceDetail() just to get the required buffer size.The second time we invoke this API to get the U-disk's detailed information with parameter ptrDeviceInterfaceDetailDatabut this time we wish it returns with truenot false.It disappointed me with error number 1784^_^. Up to nowI do not know where the problem is. But I suppose it maybe comes from the definition of structure Win32.SP_DEVICE_INTERFACE_DETAIL_DATA or allocation memory for it or passint it to the API. 5Any problememail me.Any progressemail me.^_^ Best Regards! momer

bilnaad · Answer

I think I found something to try ^_^ Win32.SP_DEVICE_INTERFACE_DETAIL_DATA devinterface = (Win32.SP_DEVICE_INTERFACE_DETAIL_DATA)Marshal.PtrToStructure ( Win32.GlobalAlloc(Win32.GPTRnBytesRequired) typeof(Win32.SP_DEVICE_INTERFACE_DETAIL_DATA) ); Win32.SP_DEVICE_INTERFACE_DETAIL_DATA* ptrDeviceInterfaceDetailData = &devinterface; --------------------- What I saw in the code is that you just created a pointer to SP_DEVICE_INTERFACE_DETAIL_DATA and didn't assign an address to it. So the pointer doesn't point anywhere(I hope I'm right ^_^). I saw this in your code above: ptrDeviceInterfaceDetailData = (Win32.SP_DEVICE_INTERFACE_DETAIL_DATA*)Win32.GlobalAlloc(Win32.GPTRnBytesRequired); This is not how to create a pointer. In my suggestion I created a structure from the IntPtr that Marshal.AllocHGlobal() returns. This is a good alternative for the API function GlobalAlloc(). Then I took it's address and stored it in variable ptrDeviceInterfaceDetailData. Try this. Maybe it works ^_^

gongdehui · Answer

YesI know what the error is.But I just do not how to modify my code to settle this problem.I suppose this error is come from the definition of structure SP_DEVICE_INTERFACE_DETAIL_DATA or memory allocation for it.Can you check my code and tell me what the problem is?

bilnaad · Answer

ErrorCode: 1784 means that the supplied buffer is not valid for the requested operation (If I translated it right from Dutch ^_^). Wich object is the buffer for this matter? DeviceInterfaceDetailData??