//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.0.30319.1
//  Copyright (c) Microsoft Corporation. All rights reserved.
 
// Metadata version: v2.0.50727
.module extern user32.dll
.assembly extern mscorlib
{
  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .zV.4..
  .ver 2:0:0:0
}
.assembly Hello
{
  .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
  .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
                                                                                                             63 65 70 74 69 6F 6E 54 68 72 6F 77 73 01 )       // ceptionThrows.
  .hash algorithm 0x00008004
  .ver 0:0:0:0
}
.module Hello.exe
// MVID: {412A0088-7664-4361-B59D-98DD5760B045}
.imagebase 0x00400000
.file alignment 0x00000200
.stackreserve 0x00100000
.subsystem 0x0003       // WINDOWS_CUI
.corflags 0x00000001    //  ILONLY
// Image base: 0x00360000
 
// =============== CLASS MEMBERS DECLARATION ===================
.class private auto ansi beforefieldinit Hello
       extends [mscorlib]System.Object
{
  .method private hidebysig static pinvokeimpl("user32.dll" winapi) 
          uint32  MessageBox(uint32 hWnd,
                             string lpText,
                             string lpTitle,
                             uint32 uType) cil managed preservesig
  {
  }
  .method private hidebysig static void  Main(string[] args) cil managed
  {
    .entrypoint
    // コード サイズ       20 (0x14)
    .maxstack  8
    IL_0000:  nop
    IL_0001:  ldc.i4.0
    IL_0002:  ldstr      "Hello, Windows API(MSIL) World!"
    IL_0007:  ldstr      "Hello, World!"
    IL_000c:  ldc.i4.0
    IL_000d:  call       uint32 Hello::MessageBox(uint32,
                                                  string,
                                                  string,
                                                  uint32)
    IL_0012:  pop
    IL_0013:  ret
  } // end of method Hello::Main
 
  .method public hidebysig specialname rtspecialname 
          instance void  .ctor() cil managed
  {
    // コード サイズ       7 (0x7)
    .maxstack  8
    IL_0000:  ldarg.0
    IL_0001:  call       instance void [mscorlib]System.Object::.ctor()
    IL_0006:  ret
  } // end of method Hello::.ctor
 
} // end of class Hello

using System.Runtime.InteropServices;
 
class Hello
{
     [DllImport("user32.dll")]
     private extern static uint MessageBox(uint hWnd, string lpText, string lpTitle, uint uType);
     static void Main(string[] args)
    {
        MessageBox( 0, "Hello, Win32 API(MSIL) World!", "Hello, World!", 0 );
    }
}

C:¥> ilasm Hello.il

---------------------------
Hello, World!
---------------------------
Hello, Win32 API(MSIL) World!
---------------------------
OK   
---------------------------