C# struct 轉換到 byte array

StructLayout: https://docs.microsoft.com/zh-tw/dotnet/api/system.runtime.interopservices.layoutkind?view=netframework-4.8
Pack: 資料欄位的對齊，這會影響最短欄位的 byte 長度

原始碼

1. [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)] 
2. public struct PollResponse 
3. { 
4.    public int AppId; 
5.    public byte Serial; 
6.    public short Station; 
7. } 
8.  
9.  
10. void Main() 
11. { 
12.    var data = new PollResponse 
13.    { 
14.        AppId = 1, 
15.        Serial = 2, 
16.        Station = 3, 
17.    }; 
18.  
19.    Type type = typeof(PollResponse); 
20.    int size = Marshal.SizeOf(type); 
21.    var bytes = new byte[size]; 
22.  
23.    /* struct to byte array */ 
24.    IntPtr ptrIn = Marshal.AllocHGlobal(size); 
25.    Marshal.StructureToPtr(data, ptrIn, true); 
26.    Marshal.Copy(ptrIn, bytes, 0, size); 
27.    Marshal.FreeHGlobal(ptrIn); 
28.  
29.    BitConverter.ToString(bytes).Dump(); 
30.    /* 01-00-00-00 - 02 - 03-00 */ 
31.  
32.  
33.    /* byte array to struct */ 
34.    IntPtr ptrOut = Marshal.AllocHGlobal(size); 
35.    Marshal.Copy(bytes, 0, ptrOut, size); 
36.    var result = (PollResponse)Marshal.PtrToStructure(ptrOut, type); 
37.    Marshal.FreeHGlobal(ptrOut); 
38.  
39.    result.Dump(); 
40.    /* { AppId = 1, Serial = 2, Station = 3 } */ 
41. } 

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
public struct PollResponse
{
    public int AppId;
    public byte Serial;
    public short Station;
}


void Main()
{
    var data = new PollResponse
    {
        AppId = 1,
        Serial = 2,
        Station = 3,
    };

    Type type = typeof(PollResponse);
    int size = Marshal.SizeOf(type);
    var bytes = new byte[size];

    /* struct to byte array */
    IntPtr ptrIn = Marshal.AllocHGlobal(size);
    Marshal.StructureToPtr(data, ptrIn, true);
    Marshal.Copy(ptrIn, bytes, 0, size);
    Marshal.FreeHGlobal(ptrIn);

    BitConverter.ToString(bytes).Dump();
    /* 01-00-00-00 - 02 - 03-00 */


    /* byte array to struct */
    IntPtr ptrOut = Marshal.AllocHGlobal(size);
    Marshal.Copy(bytes, 0, ptrOut, size);
    var result = (PollResponse)Marshal.PtrToStructure(ptrOut, type);
    Marshal.FreeHGlobal(ptrOut);

    result.Dump();
    /* { AppId = 1, Serial = 2, Station = 3 } */
}