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FileStream Constructor (String, FileMode, FileAccess, FileShare)

Initializes a new instance of the FileStream class with the specified path, creation mode, read/write permission, and sharing permission.

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

public FileStream (
	string path,
	FileMode mode,
	FileAccess access,
	FileShare share
)
public FileStream (
	String path, 
	FileMode mode, 
	FileAccess access, 
	FileShare share
)
public function FileStream (
	path : String, 
	mode : FileMode, 
	access : FileAccess, 
	share : FileShare
)

Parameters

path

A relative or absolute path for the file that the current FileStream object will encapsulate.

mode

A FileMode constant that determines how to open or create the file.

access

A FileAccess constant that determines how the file can be accessed by the FileStream object. This gets the CanRead and CanWrite properties of the FileStream object. CanSeek is true if path specifies a disk file.

share

A FileShare constant that determines how the file will be shared by processes.

Exception typeCondition

ArgumentNullException

path is a null reference (Nothing in Visual Basic).

ArgumentException

path is an empty string (""), contains only white space, or contains one or more invalid characters.

-or-

path refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment.

NotSupportedException

path refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment.

ArgumentException

path is an empty string (""), contains only white space, or contains one or more invalid characters.

FileNotFoundException

The file cannot be found, such as when mode is FileMode.Truncate or FileMode.Open, and the file specified by path does not exist. The file must already exist in these modes.

IOException

An I/O error occurs, such as specifying FileMode.CreateNew and the file specified by path already exists.

-or-

The system is running Windows 98 or Windows 98 Second Edition and share is set to FileShare.Delete.

-or-

The stream has been closed.

SecurityException

The caller does not have the required permission.

DirectoryNotFoundException

The specified path is invalid, such as being on an unmapped drive.

UnauthorizedAccessException

The access requested is not permitted by the operating system for the specified path, such as when access is Write or ReadWrite and the file or directory is set for read-only access.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

ArgumentOutOfRangeException

mode contains an invalid value.

The .NET Framework does not support direct access to physical disks through paths that are device names, such as "\\.\PHYSICALDRIVE0 ".

The path parameter can be a file name, including a file on a Universal Naming Convention (UNC) share.

The constructor is given read/write access to the file, and it is opened sharing Read access (that is, requests to open the file for writing by this or another process will fail until the FileStream object has been closed, but read attempts will succeed). The buffer size is set to the default size of 8192 bytes (8 KB).

NoteNote

path is not required to be a file stored on disk; it can be any part of a system that supports access through streams. For example, depending on the system, this class can access a physical device.

CanSeek is true for all FileStream objects that encapsulate files. If path indicates a device that does not support seeking, the CanSeek property on the resulting FileStream is false. For additional information, see CanSeek.

Caution noteCaution

When you compile a set of characters with a particular cultural setting and retrieve those same characters with a different cultural setting, the characters might not be interpretable, and could cause an exception to be thrown.

The following table lists examples of other typical or related I/O tasks.

To do this...

See the example in this topic...

Create a text file.

How to: Write Text to a File

Write to a text file.

How to: Write Text to a File

Read from a text file.

How to: Read Text from a File

Append text to a file.

How to: Open and Append to a Log File

File.AppendText

FileInfo.AppendText

Rename or move a file.

File.Move

FileInfo.MoveTo

Delete a file.

File.Delete

FileInfo.Delete

Copy a file.

File.Copy

FileInfo.CopyTo

Get the size of a file.

FileInfo.Length

Get the attributes of a file.

File.GetAttributes

Set the attributes of a file.

File.SetAttributes

Determine if a file exists.

File.Exists

Read from a binary file.

How to: Read and Write to a Newly Created Data File

Write to a binary file.

How to: Read and Write to a Newly Created Data File

Retrieve a file extension.

Path.GetExtension

Retrieve the fully qualified path of a file.

Path.GetFullPath

Retrieve the file name and extension from a path.

Path.GetFileName

Change the extension of a file.

Path.ChangeExtension

This code example is part of a larger example provided for the Lock method.

using(FileStream fileStream = new FileStream(
    "Test#@@#.dat", FileMode.OpenOrCreate, 
    FileAccess.ReadWrite, FileShare.ReadWrite))

FileStream fileStream =  new FileStream
    ("Test#@@#.dat", FileMode.OpenOrCreate, FileAccess.ReadWrite,
    FileShare.ReadWrite);

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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