Question

我的程序中有struct，我需要使用该大小为struct的实例分配托管内存。我已尝试使用sizeof()，但我收到以下错误：

Cannot take the address of, get the size of, or declare a pointer to a managed type('StatusType')

'StatusType' does not have a predefined size, therefore sizeof can only be used in an unsafe context (consider using System.RunTime.InteropServices.Marshal.SizeOf)

为什么会这样？我正确使用sizeof()（在类型名称上）。使用Marshal.SizeOf()是不正确的，因为我不使用非托管代码。什么是正确的方法？

我的struct如下：

[StructLayout(LayoutKind.Sequential)]
struct StatusType 
{
    ushort VehID;         
    ushort Location;        
    ushort Destination;     

    // Note: the way Intel Byte-swaps, the 16-bit definition below is "backwards" from the way a human may view things
    [FlagsAttribute]
    enum firstByte : uint
    {
        Battery = 2,           
        Reverse = 1,           
        LiveDINO = 1,         
        ActuallyCharging = 1,  
        BothLoads = 2,         
        AttemptingToCharge = 1 
    };

    [FlagsAttribute]
    enum secondByte : uint
    {
        Manual = 1,             
        AutoReady = 1,
        Released = 1,
        Unused1 = 1,           
        CVS = 3,              
        RequestStop = 1         
    };
    // End byte-swap note

    [FlagsAttribute]
    enum thirdByte : ushort { CmdParsingError = 8 }; 
    [FlagsAttribute]
    enum fourthByte : ushort { Error = 8 };       

    [FlagsAttribute]
    enum fifthByte : ushort
    {
        TagReadCycles = 4,                           
        Unused = 4
    };

    [FlagsAttribute]
    enum sixthByte : ushort { Condition = 8 };       

    byte[] Tag;
    ushort CCUInputs;

    [StructLayout(LayoutKind.Sequential)]
    struct union
    {
        ushort ShortCheckSum;   
        ushort DestParam;       
    }

    ushort CurrentLiftHeight;
    ushort PCLInputs;

    [FlagsAttribute]
    enum seventhByte : ushort
    {
        Unused2 = 8             
    };

    [FlagsAttribute]
    enum eigthByte : ushort
    {
        BatteryVoltage = 6,    
        Unused3 = 2
    };

    ushort LongCheckSum;       
}

Answer 1

我猜byte[] Tag;是你的问题。看看this MSDN article。

特别是这句话：

blittable类型的一维数组，例如整数数组。但是，包含blittable类型的可变数组的类型本身不会是blittable。

sizeof（）没有取我的类型名称

1 个答案: