基本介紹
在C++中可以使用#pragma pack(n)改變邊界對齊的方案，那C#的結構體怎么對應C++的結構體那？
LayoutKind.Sequential，建議使用後者，雖然前者是萬金油，不過使用起來太累又愛出錯。
C++:
1 struct Test1
2 {
3 int test1;
4 char test2;
5 __int64 test3;
6 short test4;
7 };
8
9 Test1 * __stdcall GetTest1()
10 {
11 test1.test1 = 10;
12 test1.test2 = 11;
13 test1.test3 = 12;
14 test1.test4 = 13;
15 return &test1;
16 }
C#：（這裡有兩種方案，使用LayoutKind.Explicit 和LayoutKind.Sequential，注意一下）
1 [StructLayout(LayoutKind.Explicit)]
2 public struct Test
3 {
4 [FieldOffset(0)]
5 public int test1;
6 [FieldOffset(4)]
7 public char test2;
8 [FieldOffset(8)]
9 public Int64 test3;
10 [FieldOffset(16)]
11 public short test4;
12 }
13
14 [StructLayout(LayoutKind.Sequential)]
15 public struct Test1
16 {
17 public int test1;
18 public char test2;
19 public Int64 test3;
20 public short test4;
21 }
22
23 [DllImport("TestDll")]
24 public static extern IntPtr GetTest1();
25
26 //#################################
27 IntPtr p = GetTest1();
28 Test test = (Test)Marshal.PtrToStructure(p, typeof(Test));
29 Console.WriteLine(test.test1 + test.test2 + test.test3 + test.test4);
30
31 IntPtr p1 = GetTest1(); //Auto pack
32 Test1 test1 = (Test1)Marshal.PtrToStructure(p1, typeof(Test1));
33 Console.WriteLine(test1.test1 + test1.test2 + test1.test3 + test1.test4)
