將元數據C構造為C＃

Question

請問有人可以在C＃中封送這部分C / C ++代碼嗎？

typedef struct
{
    BYTE    bCommandCode;
    BYTE    bParameterCode;

    struct
    {
        DWORD   dwSize;
        LPBYTE  lpbBody;
    }
    Data;
}
COMMAND, *LPCOMMAND;

非常感謝

Answer 1

首先，將上述結構聲明為托管結構-類似於：

    [StructLayout(LayoutKind.Sequential)]
    struct SomeStruct
    {
        byte bCommandCode;
        byte bParameterCode;

        SomeOtherStruct otherStruct;

        Data Data;
    }

    struct SomeOtherStruct
    {
        uint dwSize;
        byte lpBody;
    }

    struct Data
    {
    }

盡管您可能必須在MarshalAs使用MarshalAs屬性，以確保實際上將其編組為適當的類型。 例如，如果您想從內存中讀取此結構，則可以執行以下操作：

        var bytes = ReadBytes(address, Marshal.SizeOf(typeof(SomeStruct)), isRelative);

        fixed (byte* b = bytes)
            return (T) Marshal.PtrToStructure(new IntPtr(b), typeof (SomeStruct));

我假設您想從內存中讀取結構並將其編組為托管結構，因為否則，您甚至根本不需要Marshal 。 另外，請確保在啟用/unsafe編譯以上代碼。

Answer 2

//01. Declare 'Command' structure
public struct Command
{
    public byte CommandCode;
    public byte ParameterCode;
    public struct Data
    {
        public uint Size;
        public IntPtr Body;
    }
    public Data SendData;
}    

//02. Create & assign an instance of 'Command' structure 
//Create body array
byte[] body = { 0x33, 0x32, 0x34, 0x31, 0x30 };

//Get IntPtr from byte[] (Reference: http://stackoverflow.com/questions/537573/how-to-get-intptr-from-byte-in-c-sharp)
GCHandle pinnedArray = GCHandle.Alloc(body, GCHandleType.Pinned);
IntPtr pointer = pinnedArray.AddrOfPinnedObject();

//Create command instance
var command = new CardReaderLib.Command
                  {
                      CommandCode = 0x30,
                      ParameterCode = 0x30,
                      SendData = {
                          Size = (uint) body.Length, 
                          Body = pointer
                      }
                  };

//do your stuff

if (pinnedArray.IsAllocated)
    pinnedArray.Free();