FileStream Constructor (SafeFileHandle, FileAccess)


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Initializes a new instance of the FileStream class for the specified file handle, with the specified read/write permission.

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

public FileStream(
	SafeFileHandle handle,
	FileAccess access


Type: Microsoft.Win32.SafeHandles.SafeFileHandle

A file handle for the file that the current FileStream object will encapsulate.

Type: System.IO.FileAccess

A constant that sets the CanRead and CanWrite properties of the FileStream object.

Exception Condition

access is not a field of FileAccess.


The caller does not have the required permission.


An I/O error, such as a disk error, occurred.


The stream has been closed.


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

When Close is called, the handle is also closed and the file's handle count is decremented.

FileStream assumes that it has exclusive control over the handle. Reading, writing, or seeking while a FileStream is also holding a handle could result in data corruption. For data safety, call Flush before using the handle, and avoid calling any methods other than Close after you are done using the handle.


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.

FileShare.Read is the default for those FileStream constructors without a FileShare parameter.

For a list of common file and directory operations, see Common I-O Tasks.


for reading, writing, and appending to files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write, and FileIOPermissionAccess.Append.

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
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