Please use FireFox to view this page

Visual Basic 6 definition

Declare Function CreateFile Lib "kernel32.dll" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Any, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long

Visual Basic .NET definition

Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByRef lpSecurityAttributes As SECURITY_ATTRIBUTES, ByVal dwCreationDisposition As Integer, ByVal dwFlagsAndAttributes As Integer, ByVal hTemplateFile As Integer) As Integer

C# definition

[DllImport("kernel32.dll", SetLastError=true)] static extern int CreateFileA ( string lpFileName, int dwDesiredAccess, int dwShareMode, ref SECURITY_ATTRIBUTES lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, int hTemplateFile)

Types (click icon to expand)

SECURITY_ATTRIBUTES

Structure SECURITY_ATTRIBUTES Dim nLength As Integer Dim lpSecurityDescriptor As Integer Dim bInheritHandle As Integer End Structure

struct SECURITY_ATTRIBUTES{ int nLength; int lpSecurityDescriptor; int bInheritHandle; }

Description

CreateFile creates or opens a console, communications resource, directory (can only open), disk devices (Windows NT, 2000 only), files, mailslots, and pipes. Obviously, files are the most common thing opened by the function. The object opened can then be read from or written to, as the access level allows. After your program is finished using the handle generated by the function, it must call CloseHandle to close the open object. CreateFile Creates or opens a file object. System.IO.File class and System.IO.FileInfo class

Return Value

If an error occured, the function returns -1 (use GetLastError to get the error code). If successful, the function returns a handle to the opened or created file or other object.

Parameters

lpFileName The name of the file or other allowed object to create or open. dwDesiredAccess A combination of the following flags (if any) specifying the amounts of read/write access to the file or other object: GENERIC_READ Allow the program to read data from the file or other object. GENERIC_WRITE Allow the program to write data to the file or other object. dwShareMode A combination of the following flags (if any) specifying the amounts of read/write access to grant other programs attempting to access the file or other object while your program still has it open: FILE_SHARE_READ Allow other programs to read data from the file or other object. FILE_SHARE_WRITE Allow other programs to write data to the file or other object. lpSecurityAppributes Windows NT, 2000: A SECURITY_ATTRIBUTES structure specifying the security attributes to give the created or opened file or other object. Windows 95, 98, CE: This parameter must be 0. dwCreationDisposition Exactly one of the following flags specifying how and when to create or open the file or other object depending if it already does or does not exist: CREATE_ALWAYS Create a new file or other object. Overwrite the file or other object (i.e., delete the old one first) if it already exists. CREATE_NEW Create a new file or other object. The function fails if the file or other object already exists. OPEN_ALWAYS Open an existing file or other object. If the file or other object does not exist, it will be created. OPEN_EXISTING Open an existing file or other object. The function fails if the file or other object does not exist. TRUNCATE_EXISTING Open an existing file or other object and delete its contents. The function fails if the file or other object does not exist. dwFlagsAndAttributes The combination of the following flags specifying both the file attributes of a newly created file and other options for creating or opening the file. One flag specifying the file attributes must be included. FILE_ATTRIBUTE_ARCHIVE An archive file (which most files are). FILE_ATTRIBUTE_HIDDEN A hidden file, not normally visible to the user. FILE_ATTRIBUTE_NORMAL An attribute-less file (cannot be combined with other attributes). FILE_ATTRIBUTE_READONLY A read-only file. FILE_ATTRIBUTE_SYSTEM A system file, used exclusively by the operating system. FILE_FLAG_DELETE_ON_CLOSE Delete the file once it is closed. FILE_FLAG_NO_BUFFERING Do not use any buffers or caches. If used, the following things must be done: access to the file must begin at whole number multiples of the disk's sector size; the amounts of data accessed must be a whole number multiple of the disk's sector size; and buffer addresses for I/O operations must be aligned on whole number multiples of the disk's sector size. FILE_FLAG_OVERLAPPED Allow asynchronous I/O; i.e., allow the file to be read from and written to simultaneously. If used, functions that read and write to the file must specify the OVERLAPPED structure identifying the file pointer. (Windows 95, 98, CE: Overlapped files are not supported, although other overlapped objects are.) FILE_FLAG_POSIX_SEMANTICS Allow file names to be case-sensitive. FILE_FLAG_RANDOM_ACCESS Optimize the file cache for random access (skipping around to various parts of the file). FILE_FLAG_SEQUENTIAL_SCAN Optimize the file cache for sequential access (starting at the beginning and continuing to the end of the file). FILE_FLAG_WRITE_THROUGH Bypass any disk cache and instead read and write directly to the file. hTemplateFile A handle to an open file to copy the attributes of, or 0 to not copy the attributes of any open file.

Constants

Const GENERIC_READ = &H80000000 Const GENERIC_WRITE = &H40000000 Const FILE_SHARE_READ = &H1 Const FILE_SHARE_WRITE = &H2 Const CREATE_ALWAYS = 2 Const CREATE_NEW = 1 Const OPEN_ALWAYS = 4 Const OPEN_EXISTING = 3 Const TRUNCATE_EXISTING = 5 Const FILE_ATTRIBUTE_ARCHIVE = &H20 Const FILE_ATTRIBUTE_HIDDEN = &H2 Const FILE_ATTRIBUTE_NORMAL = &H80 Const FILE_ATTRIBUTE_READONLY = &H1 Const FILE_ATTRIBUTE_SYSTEM = &H4 Const FILE_FLAG_DELETE_ON_CLOSE = &H4000000 Const FILE_FLAG_NO_BUFFERING = &H20000000 Const FILE_FLAG_OVERLAPPED = &H40000000 Const FILE_FLAG_POSIX_SEMANTICS = &H1000000 Const FILE_FLAG_RANDOM_ACCESS = &H10000000 Const FILE_FLAG_SEQUENTIAL_SCAN = &H8000000 Const FILE_FLAG_WRITE_THROUGH = &H80000000

Further Information:

For further information on Windows API functions such as these, and how to use these API's in your C# and VB.NET applications, please refer to the book 'Network programming in .NET' (Buy at Amazon UK) (Buy at Amazon US)

Visual Basic 6 example source code

Visual Basic .NET example source code

C# example source code

Provide a code example

C#
VB.NET
VB6