FileStream Constructor (IntPtr, FileAccess, Boolean, Int32)


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Note: This API is now obsolete.

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

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

[ObsoleteAttribute("This constructor has been deprecated.  Please use new FileStream(SafeFileHandle handle, FileAccess access, int bufferSize) instead, and optionally make a new SafeFileHandle with ownsHandle=false if needed.")]
public FileStream(
	IntPtr handle,
	FileAccess access,
	bool ownsHandle,
	int bufferSize


Type: System.IntPtr

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

Type: System.IO.FileAccess

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

Type: System.Boolean

true if the file handle will be owned by this FileStream instance; otherwise, false.

Type: System.Int32

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

Exception Condition

bufferSize 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.

The FileStream object is given the specified access to the file. The ownership of the handle will be as specified. If this FileStream owns the handle, a call to the Close method will also close the handle. In particular, the file's handle count is decremented. The FileStream object is given the specified buffer size.

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.

.NET Framework
Available since 1.1
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