Error 1784 when invoke SetupDiGetDeviceInterfaceDetail() in C#

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 MSDN,and you can see what we to do with the parameter ptrDeviceInterfaceDetailData.And I suppose GlobalAlloc() can offer it a certain address. In your last letter,you 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.So,now I hope I can give you some useful tips. 1,below to the breakpoint 6,the last one, pls change Marshal.GetLastWin32Error() with Win32.GetLastError(),then you can get the Error number 122,not 8 any more.^_^This is the first thing. 2,Here,we just care about the above problem,error 1784,so you do not need to know other code which I not mention here later. At breakpoint 1,method 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-disk,and then we can format this U-disk.So,at first we must get the U-disk's devicepath.The mothod refreshalldevicespathes(temp) invokes many other methods,but all of them just cooperate to enumerate the U-disk's devicepath.And here,we do not need to care about the parameter temp,and you can see that it never be used in later code.I will use it when we can enumerate the U-disk's devicepath,and tell you what role it acts. 3,At 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 class,so we use enum_disk() to enumetate all the DISK device instance on the local machine,and 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 example,a material mp3 is an instance of usb device class,and the flash(or disk) inside is its first child device,which belongs to DISK device class.If one or more cards(such as MS,FC,etc.) can attach to this mp3,then the card(s) is the second child,third child,etc. of this mp3.But what we want to get is the devicepath of the first child(U-disk or flash). 4,After you have done the 1 step,click the debug button,when it finish initializing th UI,attach your mp3 to PC,and then run to breakpoint 1,step by step,you can see how those methods enumate to the "diskdeviceinfo",and as you go to breakpoint 6,you will get error number 122,it's what we want,and 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 ptrDeviceInterfaceDetailData,but this time we wish it returns with true,not false.It disappointed me with error number 1784^_^. Up to now,I 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. 5,Any problem,email me.Any progress,email me.^_^ Best Regards! momer

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.GPTR,nBytesRequired), 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.GPTR,nBytesRequired); 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 ^_^

Yes,I 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?

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??