C#でレガシーな事をする方向けのまとめ ref: http://qiita.com/hmuronaka/items/619f8889e36c7b5db92d

file0.txt

    using System.Runtime.InteropServices;

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct Header
    {
        ushort len;
        byte firstAddress;
        byte secondAddress;
        byte sourceAddress;
    }

file1.txt

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct A
    {
        public int a;
        public byte b;

        public static readonly int len;
        static A()
        {
            len = Marshal.SizeOf(typeof(A)); =>  5
        }
    }

file10.txt

 struct A
 {
   int a;
   int b;
 }

 void foo()
 {
   A a = new A() { a=10,b=20 };
   A b = a; // オブジェクトの参照ではなく値のコピーが行われる。
   b.a = 30; => a.a==10 b.a==30
 }   

file11.txt

 void init()
 {
     Func<int,int,int> addDelegate = delegate(int a,int b) {
        return a + b;
     }

     int sum = foo(1,2, addDelegate);
 }

 int foo(int a, int b, Func<int,int,int> operation) {
   return operation(a,b);
 }

file12.txt

delegate void fucn();

 func myFunc = null;

 void foo() {
  if( myFunc != null ) {
   myFunc();
  }
 }

file13.txt

 void otherThreadMain()
 {
   items...

   listView.Invoke((MethodInvoker)delegate()
   {
     listView.Clear();
     listView.AddRange(items);
   },null);
 }

file14.txt

 using System.Runtime.InteropServices;

 [System.Runtime.InteropServices.DllImport("MyDll.dll" ,CallingConvention=CallingConvention.ThisCall, EntryPoint = "? get@CMyFunc@@QAEHHH@Z")]
 extern Int32 get(Int32 a, Int32 b);

file15.txt

 class CUDPSocket;
 class DLLDECLAR CMyTest
 {
 private:
    CUDPSocket* mSocket;

 public:
    CMyTest(void);
    virtual ~ CMyTest(void);

 public:
    INT get(INT a, INT b);
 };

 // new 用
 DLLDECLAR CMyTest* newMyTest();
 // delete用
 DLLDECLAR void releaseMyTest(CMyTest* obj);

file16.txt

 namespace XXX
 {
     public class MyTest : IDisposable 
     {
         // EntryPointはDependency Walkerなどで調べる...
         [System.Runtime.InteropServices.DllImport("MyTestDll.dll",  EntryPoint = "?newMyTest@@YAPAVCMyTest@@XZ")]
         static extern IntPtr newMyTest();
         [System.Runtime.InteropServices.DllImport("MyTest.dll",  EntryPoint = "?releaseMyTest@@YAXPAVCMyTest@@@Z")]
        static extern void deleteMyTest(IntPtr obj);
         // メソッドは呼び出し規約を明示する必要がある。
         [System.Runtime.InteropServices.DllImport("MyTestDll.dll"  ,CallingConvention=CallingConvention.ThisCall, EntryPoint = "? get@CMyTest@@QAEHHH@Z")]
         static extern Int32 get(IntPtr obj, Int32 a, Int32 b);
         [System.Runtime.InteropServices.DllImport("MyTest.dll",  EntryPoint="?addDll@@YAHHH@Z")]
         static extern Int32 addDll(Int32 a, Int32 b);

         IntPtr mBody;

         public MyTest()
         {
             this.mBody = newMyTest();
         }

         public void Dispose()
         {
             deleteMyTest(this.mBody);
         }

         public Int32 Get(Int32 a, Int32 b)
         {

             return get(this.mBody, a, b);
         }

         public static Int32 Add(Int32 a, Int32 b)
         {
             return addDll(a, b);
         }
     }
 }

file17.txt

 ListBox listBox1;

 public void onReceiveAlive(Object sender, InetEvent evt)
 {
   // 他スレッドから呼び出された場合.
   if (listBox1.InvokeRequired)
   {
     listBox1.Invoke(new Action<Object, InetEvent>(onReceiveAlive), 
                     new Object[]     { sender, evt });
     return;
   }

   // 通常の処理.
   listBox1.Items.Insert(0, "test");
 }

file2.txt

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct B
    {
        public byte a;
        public A b;

        public static readonly int len;
        static B()
        {
            len = Marshal.SizeOf(typeof(B)); => 6 (A.len + sizeof(b))
        }
    }

file3.txt

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct A
    {
        public int a;
        public byte[] b;

        public static readonly int len;
        static A()
        {
            len = Marshal.SizeOf(typeof(A)); => 8
        }
    }

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct B
    {
        public byte a;
        public A b;

        public static readonly int len;
        static B()
        {
            len = Marshal.SizeOf(typeof(B)); => 9 (A.len + sizeof(b))
        }
    }

file4.txt

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct A
    {
        public int a;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
        public byte[] b;

        public static readonly int len;
        static A()
        {
            len = Marshal.SizeOf(typeof(A)); => 6
        }
    }

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct B
    {
        public byte a;
        public A b;

        public static readonly int len;
        static B()
        {
            len = Marshal.SizeOf(typeof(B)); => 7 (A.len + sizeof(a)) 
        }
    }

file5.txt

 struct AAA
 {
   [MarshalAs(UnmanagedType.ByValArray, SizeConst=3)]
   public byte[] test;
 }

file6.txt

 struct AAA
 {
   public byte[] test;
 }

file7.txt

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct A
    {
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
        public int a; => MarshalAsを指定して非配列はNG. Marshal系のメソッドを利用するとException発生.

        public static readonly int len;
        static A()
        {
            len = Marshal.SizeOf(typeof(A));
        }
    }

file8.txt

    public struct A
    {
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 2)]
        public byte[] a;

        public static readonly int len;
        static A()
        {
            len = Marshal.SizeOf(typeof(A));
        }
    }

    void foo()
    {
      A a = new A();
      a.a = new byte[2]; => newの必要あり。サイズがSizeConstと一致の必要有
    }

file9.txt

      public static void byteToStruct<T>(byte[] buffer, int pos, int typeLen, out T result)
        {
            int endPos = pos + typeLen;
            if (endPos > buffer.Length)
            {
                throw new Exception("サイズ不正[endPos," + endPos.ToString() + "][buflen," + buffer.Length.ToString() + "]");
            }

            T obj;
            IntPtr ptr = Marshal.AllocHGlobal(typeLen);
            try
            {
                Marshal.Copy(buffer, pos, ptr, typeLen);
                obj = (T)Marshal.PtrToStructure(ptr, typeof(T));
                result = obj;
            }
            finally
            {
                if (IntPtr.Zero != ptr)
                {
                    Marshal.FreeHGlobal(ptr);
                }
            }
        }


         public static void structToByte<T>(T obj, int typeLen, byte[] buffer, int pos)
        {
            int endPos = pos + typeLen;
            if (endPos > buffer.Length)
            {
                throw new Exception("サイズ不正[endPos," + endPos.ToString() + "][buflen," + buffer.Length.ToString() + "]");
            }
            IntPtr ptr = Marshal.AllocHGlobal(typeLen);
            try
            {
                Marshal.StructureToPtr(obj, ptr, false);
                Marshal.Copy(ptr, buffer, pos, typeLen);
            }
            finally
            {
                if (IntPtr.Zero != ptr)
                {
                    Marshal.FreeHGlobal(ptr);
                }
            }
        }