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File.Open Method (String, FileMode, FileAccess, FileShare)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

When it is called by trusted applications, opens a FileStream on the specified path, having the specified mode with read, write, or read/write access and the specified sharing option.

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

Syntax

'Declaration
Public Shared Function Open ( _
    path As String, _
    mode As FileMode, _
    access As FileAccess, _
    share As FileShare _
) As FileStream

public static FileStream Open(
    string path,
    FileMode mode,
    FileAccess access,
    FileShare share
)

Parameters

  • mode
    Type: System.IO.FileMode
    A FileMode value that specifies whether a file is created if one does not exist, and determines whether the contents of existing files are retained or overwritten.

Return Value

Type: System.IO.FileStream
A FileStream on the specified path, having the specified mode with read, write, or read/write access and the specified sharing option.

Exceptions

Exception Condition
ArgumentException

path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by GetInvalidPathChars.

-or-

access specified Read and mode specified Create, CreateNew, Truncate, or Append.
ArgumentNullException

path is nulla null reference (Nothing in Visual Basic).
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.
DirectoryNotFoundException

The specified path is invalid, (for example, it is on an unmapped drive).
IOException

An I/O error occurred while opening the file.
UnauthorizedAccessException

path specified a file that is read-only and access is not Read.

-or-

path specified a directory.

-or-

The caller does not have the required permission.
ArgumentOutOfRangeException

mode, access, or share specified an invalid value.
FileNotFoundException

The file specified in path was not found.
NotSupportedException

path is in an invalid format.

Remarks

For more information about trusted applications, see Trusted Applications.

Platform Notes

Silverlight for Windows Phone Silverlight for Windows Phone

 This member has a SecurityCriticalAttribute attribute on Silverlight for Windows Phone, because the attribute was present in Silverlight 3. This attribute restricts this member to internal use. Application code that uses this member throws a MethodAccessException.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.