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Calling WriteFileEx() from C# (including supporting structures, constants, etc...)

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Today I had the unfortunate and tedious task of calling the WriteFileEx API from a managed application. For you consuming pleasure I have posted the source code for a console app that creates a file called history.txt in the local directory and writes the word “test” into it.

I updated the API information on Pinvoke.net so you can grab it from there as well.

 

 

 

using System;

using System.Runtime.InteropServices;

namespace ConsoleApplication8

{

       struct OVERLAPPED

       {

              public IntPtr Internal;

              public IntPtr InternalHigh;

              public UInt32 Offset;

              public UInt32 OffsetHigh;

              public IntPtr hEvent;

       };

       class Class1

       {

              public const int FILE_READ_DATA = 0x0001; // file & pipe

              public const int FILE_LIST_DIRECTORY = 0x0001; // directory

              public const int FILE_WRITE_DATA = 0x0002; // file & pipe

              public const int FILE_ADD_FILE = 0x0002; // directory

              public const int FILE_APPEND_DATA = 0x0004; // file

              public const int FILE_ADD_SUBDIRECTORY = 0x0004; // directory

              public const int FILE_CREATE_PIPE_INSTANCE = 0x0004; // named pipe

              public const int FILE_READ_EA = 0x0008; // file & directory

              public const int FILE_WRITE_EA = 0x0010; // file & directory

              public const int FILE_EXECUTE = 0x0020; // file

              public const int FILE_TRAVERSE = 0x0020; // directory

              public const int FILE_DELETE_CHILD = 0x0040; // directory

              public const int FILE_READ_ATTRIBUTES = 0x0080; // all

              public const int FILE_WRITE_ATTRIBUTES = 0x0100; // all

              public const long STANDARD_RIGHTS_REQUIRED = 0x000F0000L;

              public const long READ_CONTROL = 0x00020000L;

              public const long SYNCHRONIZE = 0x00100000L;

              public const long STANDARD_RIGHTS_READ = READ_CONTROL;

              public const long STANDARD_RIGHTS_WRITE = READ_CONTROL;

              public const long STANDARD_RIGHTS_EXECUTE = READ_CONTROL;

              public const long STANDARD_RIGHTS_ALL = 0x001F0000L;

              public const long SPECIFIC_RIGHTS_ALL = 0x0000FFFFL;

              public const long FILE_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0x1FF;

              public const long FILE_GENERIC_READ = STANDARD_RIGHTS_READ |

                     FILE_READ_DATA |

                     FILE_READ_ATTRIBUTES |

                     FILE_READ_EA |

                     SYNCHRONIZE;

              public const long FILE_GENERIC_WRITE = STANDARD_RIGHTS_WRITE |

                     FILE_WRITE_DATA |

                     FILE_WRITE_ATTRIBUTES |

                     FILE_WRITE_EA |

                     FILE_APPEND_DATA |

                     SYNCHRONIZE;

              public const long FILE_GENERIC_EXECUTE = STANDARD_RIGHTS_EXECUTE |

                     FILE_READ_ATTRIBUTES |

                     FILE_EXECUTE |

                     SYNCHRONIZE;

              public const int FILE_SHARE_READ = 0x00000001;

              public const int FILE_SHARE_WRITE = 0x00000002;

              public const int FILE_SHARE_DELETE = 0x00000004;

              public const int FILE_ATTRIBUTE_READONLY = 0x00000001;

              public const int FILE_ATTRIBUTE_HIDDEN = 0x00000002;

              public const int FILE_ATTRIBUTE_SYSTEM = 0x00000004;

              public const int FILE_ATTRIBUTE_DIRECTORY = 0x00000010;

              public const int FILE_ATTRIBUTE_ARCHIVE = 0x00000020;

              public const int FILE_ATTRIBUTE_DEVICE = 0x00000040;

              public const int FILE_ATTRIBUTE_NORMAL = 0x00000080;

              public const int FILE_ATTRIBUTE_TEMPORARY = 0x00000100;

              public const int FILE_ATTRIBUTE_SPARSE_FILE = 0x00000200;

              public const int FILE_ATTRIBUTE_REPARSE_POINT = 0x00000400;

              public const int FILE_ATTRIBUTE_COMPRESSED = 0x00000800;

              public const int FILE_ATTRIBUTE_OFFLINE = 0x00001000;

              public const int FILE_ATTRIBUTE_NOT_CONTENT_INDEXED = 0x00002000;

              public const int FILE_ATTRIBUTE_ENCRYPTED = 0x00004000;

              public const int FILE_NOTIFY_CHANGE_FILE_NAME = 0x00000001;

              public const int FILE_NOTIFY_CHANGE_DIR_NAME = 0x00000002;

              public const int FILE_NOTIFY_CHANGE_ATTRIBUTES = 0x00000004;

              public const int FILE_NOTIFY_CHANGE_SIZE = 0x00000008;

              public const int FILE_NOTIFY_CHANGE_LAST_WRITE = 0x00000010;

              public const int FILE_NOTIFY_CHANGE_LAST_ACCESS = 0x00000020;

       public const int FILE_NOTIFY_CHANGE_CREATION = 0x00000040;

              public const int FILE_NOTIFY_CHANGE_SECURITY = 0x00000100;

              public const int FILE_ACTION_ADDED = 0x00000001;

              public const int FILE_ACTION_REMOVED = 0x00000002;

              public const int FILE_ACTION_MODIFIED = 0x00000003;

              public const int FILE_ACTION_RENAMED_OLD_NAME = 0x00000004;

              public const int FILE_ACTION_RENAMED_NEW_NAME = 0x00000005;

              public const int MAILSLOT_NO_MESSAGE = -1;

              public const int MAILSLOT_WAIT_FOREVER = -1;

              public const int FILE_CASE_SENSITIVE_SEARCH = 0x00000001;

              public const int FILE_CASE_PRESERVED_NAMES = 0x00000002;

              public const int FILE_UNICODE_ON_DISK = 0x00000004;

              public const int FILE_PERSISTENT_ACLS = 0x00000008;

              public const int FILE_FILE_COMPRESSION = 0x00000010;

              public const int FILE_VOLUME_QUOTAS = 0x00000020;

              public const int FILE_SUPPORTS_SPARSE_FILES = 0x00000040;

              public const int FILE_SUPPORTS_REPARSE_POINTS = 0x00000080;

              public const int FILE_SUPPORTS_REMOTE_STORAGE = 0x00000100;

              public const int FILE_VOLUME_IS_COMPRESSED = 0x00008000;

              public const int FILE_SUPPORTS_OBJECT_IDS = 0x00010000;

              public const int FILE_SUPPORTS_ENCRYPTION = 0x00020000;

              public const int FILE_NAMED_STREAMS = 0x00040000;

              public const int FILE_READ_ONLY_VOLUME = 0x00080000;

              public const int CREATE_ALWAYS = 2;

       public delegate void WriteFileCompletionDelegate(UInt32 dwErrorCode,

                     UInt32 dwNumberOfBytesTransfered, ref OVERLAPPED lpOverlapped);

              [DllImport("kernel32.dll", SetLastError=true)]

              static extern bool WriteFileEx(IntPtr hFile, byte [] lpBuffer,

                     uint nNumberOfBytesToWrite, [In] ref OVERLAPPED lpOverlapped,

                     WriteFileCompletionDelegate lpCompletionRoutine);

             

              [DllImport("kernel32.dll", SetLastError=true)]

              static extern IntPtr CreateFile(string lpFileName, uint dwDesiredAccess,

                     uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition,

                     uint dwFlagsAndAttributes, IntPtr hTemplateFile);

              [DllImport("kernel32.dll", SetLastError=true)]

              static extern bool CloseHandle(IntPtr hObject);

             

              [STAThread]

              static void Main(string[] args)

              {

                     IntPtr hfile;

                     hfile = CreateFile(@"history.txt", (UInt32)FILE_ALL_ACCESS, FILE_SHARE_WRITE, IntPtr.Zero, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero);

                    

                     OVERLAPPED ol = new OVERLAPPED();

                     WriteFileEx(hfile, new byte[] { (byte)'t', (byte)'e', (byte)'s', (byte)'t' }, 4, ref ol, new WriteFileCompletionDelegate(Class1.callback));

                     CloseHandle(hfile);

              }

              private static void callback(UInt32 dwErrorCode, UInt32 dwNumberOfBytesTransfered, ref OVERLAPPED lpOverlapped)

              {

                     Console.Write("In the callback");

                     Console.Read();

              }

       }

}

Comments

  • Anonymous
    July 07, 2004
    Woudln't it make more sense to put those flags into enums? You can call them Enum1, Enum2 and so on…
  • Anonymous
    July 07, 2004
    It certainly would make more sense but I was just wanting to get a working sample, nothing that was real-world ready.

  • Anonymous
    July 09, 2004
    Glad to see you are back to bloggn' Roberto. ;)