FileStream Constructor (SafeFileHandle, FileAccess, Int32)

FileStream Constructor (SafeFileHandle, FileAccess, Int32)


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

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

public FileStream(
	SafeFileHandle handle,
	FileAccess access,
	int bufferSize


Type: Microsoft.Win32.SafeHandles.SafeFileHandle

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

Type: System.IO.FileAccess

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

Type: System.Int32

A positive Int32 value greater than 0 indicating the buffer size. The default buffer size is 4096.

Exception Condition

The handle parameter is an invalid handle.


The handle parameter is a synchronous handle and it was used asynchronously.


The bufferSize parameter is negative.


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


The stream has been closed.


The caller does not have the required permission.


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.

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. Alternately, read and write to the handle before calling this FileStream constructor.

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


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.

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.


for permission to call unmanaged code. Associated enumerations: SecurityPermissionFlag.UnmanagedCode

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