C++中的union结构体怎么转换成C#？

Question

C++中的union结构体怎么转换成C#？ 

Answer 1

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[StructLayout(LayoutKind.Explicit, Size=2)] struct TokenValue { [FieldOffset(0)] [MarshalAs(UnmanagedType.U1)] public byte _cval; [FieldOffset(1)] [MarshalAs(UnmanagedType.U1)]  public byte _ival; [FieldOffset(0)] public ushort flags; }

Answer 2

        public struct dash_generic_param
        {
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 30)]
            public short[] raw_data;
        }
        //public struct dash_generic_param
        //{
        //    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
        //    public ushort[] values;
        //    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 11)]
        //    public ushort[] reserved;
        //    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
        //    public ushort[] limit;
        //}
        // 结构体按你需求，2选1
        public struct DashParamPacket {	
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 34)]
            public ushort[] raw_data;
        }
        //public struct DashParamPacket {	
        //     public ushort pre_id;
        //     public byte token;
        //     public byte r1;
        //     public dash_generic_param data;
        //     public byte major_id;
        //     public byte minor_id;
        //     public ushort r2;
        //}

        // 例如c++库里接口名为GetPacket，DashParamPacket是c#定义的与C++中内存对齐的结构体
        [DllImport("xxx.dll")]
        public static extern bool GetPacket(ref DashParamPacket parm);

        static void Main(string[] args)
        {
            DashParamPacket param = new DashParamPacket(); // C#里的结构体
            GetPacket(ref param); // 如果C++接口定义的结构体指针，可以直接用引用

            // 如果需要转void*使用，可以用marhal库来回转
            IntPtr p = In