“Invalid managed/unmanaged type combination.”的意思是什么？

Question

我有以下结构体：

    [StructLayout(LayoutKind.Auto,Pack=0)]
    private unsafe struct BIRDSYSTEMCONFIG
    {
        public byte bySystemStatus;
        public byte byError;
        public byte byNumDevices;
        public byte byNumServers;
        public byte byXmtrNum;
        public ushort wXtalSpeed;
        public double dMeasurementRate;
        public byte byChassisNum;
        public byte byNumChassisDevices;
        public byte byFirstDeviceNum;
        public ushort wSoftwareRev;
        public fixed byte byFlockStatus[127];
    }

基于C++结构体：

typedef struct tagBIRDSYSTEMCONFIG
{
    BYTE    bySystemStatus;     // current system status (see bird system status bits, above)
    BYTE    byError;            // error code flagged by server or master bird
    BYTE    byNumDevices;       // number of devices in system
    BYTE    byNumServers;       // number of servers in system
    BYTE    byXmtrNum;          // transmitter number (see transmitter number bits, above)
    WORD    wXtalSpeed;         // crystal speed in MHz
    double  dMeasurementRate;   // measurement rate in frames per second
    BYTE    byChassisNum;       // chassis number
    BYTE    byNumChassisDevices; // number of devices within this chassis
    BYTE    byFirstDeviceNum;   // number of first device in this chassis
    WORD    wSoftwareRev;       // software revision of server application or master bird
    BYTE    byFlockStatus[BIRD_MAX_DEVICE_NUM + 1]; // status of all devices in flock, indexed by bird number (see note in BIRDFRAME definition) - see bird flock status bits, above
} 
BIRDSYSTEMCONFIG;

以下是相关函数:

    [DllImport(@"Bird.dll", CallingConvention = CallingConvention.Cdecl)]
    private static extern bool birdGetSystemConfig(
        int nGroupID,
        ref BIRDSYSTEMCONFIG psyscfg,
        bool bGetDriverCopy
        );

基于C++函数:

BOOL DLLEXPORT birdGetSystemConfig(int nGroupID, BIRDSYSTEMCONFIG *psyscfg, BOOL bGetDriverCopy = FALSE);

我通常这样调用：

BIRDSYSTEMCONFIG sysconf = new BIRDSYSTEMCONFIG();
birdGetSystemConfig(1, ref sysconf, true);

然而，我遇到了一个错误：

无法编组“参数#2”：无效的托管/非托管类型组合。

这是什么意思？为什么会出现这个错误？如何克服它？欢迎提供所有建议！

- Tom Wright

---

你应该发布原始的C++结构体。 - R. Martinho Fernandes

请看这里：http://www.groupsrv.com/dotnet/about24649.html - sajoshi

Answer 1

原来我只需要更改以下内容：

[StructLayout(LayoutKind.Auto,Pack=0)]

To

[StructLayout(LayoutKind.Sequential,Pack=0)]

由于这个问题不仅仅是如何解决，我会暂时保持开放状态。了解更多关于这个错误的信息会很有帮助。

- Tom Wright