Createfile工作，但在FileStream Construction上句柄无效

Question

我正在尝试通过HID连接到Unity3D中的Wiimote。

当我调用CreateFile()(来自kernel32)时，返回一个"有效"的指针，我甚至可以通过HidD_GetPreparsedData和HidP_GetCaps获得Wiimote的功能。Buffer-size等返回，是我期望的大小。但是，当我试图在句柄上打开FileStream时，它错误地显示"无效句柄"。

如果我可以GetCaps，这个句柄怎么可能在这里无效?Marshal32.GetLastWinError()也返回0。

相关代码:

int i = 0;
foreach (string devPath in devicePaths)
{
    Debug.Log(i);
    i++;
    if (devPath.Contains(VID_NINTENDO))
        if (devPath.Contains(PID_WIIMOTE)) // ADD OTHER PID (IF EVER FOUND)
        {
            try
            {
                IntPtr dev_Handle = CreateFile(devPath, FileAccess.Read | FileAccess.Write, FileShare.Read | FileShare.Write, IntPtr.Zero, FileMode.Open, FILE_FLAG_OVERLAPPED, IntPtr.Zero); // Gives a "Valid" pointer
                IntPtr device_data = IntPtr.Zero;
                int inputLength = 0;
                try
                {
                    if (!HidD_GetPreparsedData(dev_Handle, out device_data))
                    {
                        throw new HIDException("Unable to get Preparsed data from device");
                    }
                    HidCaps device_capabilities; // Struct to contain inputlength etc.
                    HidP_GetCaps(device_data, out device_capabilities);
                    inputLength = device_capabilities.InputReportByteLength;
                    int outputLength = device_capabilities.OutputReportByteLength;
                    FileStream stream = new FileStream(dev_Handle, FileAccess.Read | FileAccess.Write, true, inputLength); // INVALID HANDLE
                    //FileStream stream = new FileStream(new SafeFileHandle(dev_Handle, false), FileAccess.Read | FileAccess.Write, inputLength, true); // Invalid Handle
                    //FileStream stream = new FileStream(dev_Handle, FileAccess.Read | FileAccess.Write, true, inputLength); // Invalid Handle
                    //FileStream stream = new FileStream(devPath, FileMode.Open, FileAccess.Read | FileAccess.Write, FileShare.Read | FileShare.Write, inputLength); // nullref (The file isnt being created in this path)
                    Debug.Log(dev_Handle);
                }
                catch (Exception e)
                {
                    HandleException(e, "HIDException");
                }
                finally
                {
                    HidD_FreePreparsedData(ref device_data);
                }
            }
            catch (Exception e)
            {
                HandleException(e, "HIDException");
            }
        }                            
    }

同样，在一个常规的c#项目中，它简单地工作:(尽管我必须在FileStream构造函数中设置useAsync = true(尽管在Unity中仍然是Invalid Handle)

Answer 1

最后通过使用kernel32.dll的ReadFile方法使其工作…显然Unity有SafeFileHandles的问题…:年代使用此API:http://buiba.blogspot.nl/2009/06/using-winapi-createfile-readfile.html使阅读成为可能