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class System.IO.FileStream
Assembly: System.Runtime
Inheritance: object → MarshalByRefObject → Stream → FileStream
Provides a <see cref="T:System.IO.Stream" /> for a file, supporting both synchronous and asynchronous read and write operations.
Properties
public
bool
CanRead
Gets a value that indicates whether the current stream supports reading.
public
bool
CanSeek
Gets a value that indicates whether the current stream supports seeking.
public
bool
CanWrite
Gets a value that indicates whether the current stream supports writing.
public
nint
Handle
Gets the operating system file handle for the file that the current <see langword="FileStream" /> object encapsulates.
public
bool
IsAsync
Gets a value that indicates whether the <see langword="FileStream" /> was opened asynchronously or synchronously.
public
long
Length
Gets the length in bytes of the stream.
public
string
Name
Gets the absolute path of the file opened in the <see langword="FileStream" /> .
public
long
Position
Gets or sets the current position of this stream.
SafeFileHandle
Gets a <see cref="T:Microsoft.Win32.SafeHandles.SafeFileHandle" /> object that represents the operating system file handle for the file that the current <see cref="T:System.IO.FileStream" /> object encapsulates.
public
bool
CanTimeout
Gets a value that determines whether the current stream can time out.
public
int
ReadTimeout
Gets or sets a value, in milliseconds, that determines how long the stream will attempt to read before timing out.
public
int
WriteTimeout
Gets or sets a value, in milliseconds, that determines how long the stream will attempt to write before timing out.
Methods
public
IAsyncResult
BeginRead(byte[] buffer,
int offset,
int count,
AsyncCallback callback,
object state)
buffer
The buffer to read data into.
offset
The byte offset in <paramref name="array" /> at which to begin reading.
count
The maximum number of bytes to read.
callback
The method to be called when the asynchronous read operation is completed.
state
A user-provided object that distinguishes this particular asynchronous read request from other requests.
Returns An object that references the asynchronous read.
Begins an asynchronous read operation. Consider using <see cref="M:System.IO.FileStream.ReadAsync(System.Byte[],System.Int32,System.Int32,System.Threading.CancellationToken)" /> instead.
public
IAsyncResult
BeginWrite(byte[] buffer,
int offset,
int count,
AsyncCallback callback,
object state)
buffer
The buffer containing data to write to the current stream.
offset
The zero-based byte offset in <paramref name="array" /> at which to begin copying bytes to the current stream.
count
The maximum number of bytes to write.
callback
The method to be called when the asynchronous write operation is completed.
state
A user-provided object that distinguishes this particular asynchronous write request from other requests.
Returns An object that references the asynchronous write.
Begins an asynchronous write operation. Consider using <see cref="M:System.IO.FileStream.WriteAsync(System.Byte[],System.Int32,System.Int32,System.Threading.CancellationToken)" /> instead.
public
void
CopyTo(Stream destination,
int bufferSize)
destination
The stream to which the contents of the current stream will be copied.
bufferSize
The size of the buffer. This value must be greater than zero.
Reads the bytes from the current stream and writes them to another stream, using a specified buffer size. Both streams positions are advanced by the number of bytes copied.
public
Threading.Tasks.Task
CopyToAsync(Stream destination,
int bufferSize,
Threading.CancellationToken cancellationToken)
destination
The stream to which the contents of the current file stream will be copied.
bufferSize
The size, in bytes, of the buffer. This value must be greater than zero.
cancellationToken
The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" /> .
Returns A task that represents the asynchronous copy operation.
Asynchronously reads the bytes from the current file stream and writes them to another stream, using a specified buffer size and cancellation token.
protected
void
Dispose(bool disposing)
disposing
<see langword="true" /> to release both managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.
Releases the unmanaged resources used by the <see cref="T:System.IO.FileStream" /> and optionally releases the managed resources.
public
Threading.Tasks.ValueTask
DisposeAsync() Returns A task that represents the asynchronous dispose operation.
Asynchronously releases the unmanaged resources used by the <see cref="T:System.IO.FileStream" /> .
public
int
EndRead(IAsyncResult asyncResult)
asyncResult
The reference to the pending asynchronous request to wait for.
Returns The number of bytes read from the stream, between 0 and the number of bytes you requested. Streams only return 0 at the end of the stream, otherwise, they should block until at least 1 byte is available.
Waits for the pending asynchronous read operation to complete. (Consider using <see cref="M:System.IO.FileStream.ReadAsync(System.Byte[],System.Int32,System.Int32,System.Threading.CancellationToken)" /> instead.)
Ends an asynchronous write operation and blocks until the I/O operation is complete. (Consider using <see cref="M:System.IO.FileStream.WriteAsync(System.Byte[],System.Int32,System.Int32,System.Threading.CancellationToken)" /> instead.)
protected
void
Finalize()
Ensures that resources are freed and other cleanup operations are performed when the garbage collector reclaims the <see langword="FileStream" /> .
public
void
Flush()
Clears buffers for this stream and causes any buffered data to be written to the file.
public
void
Flush(bool flushToDisk)
flushToDisk
<see langword="true" /> to flush all intermediate file buffers; otherwise, <see langword="false" /> .
Clears buffers for this stream and causes any buffered data to be written to the file, and also clears all intermediate file buffers.
public
Threading.Tasks.Task
FlushAsync(Threading.CancellationToken cancellationToken)
cancellationToken
The token to monitor for cancellation requests.
Returns A task that represents the asynchronous flush operation.
Asynchronously clears all buffers for this stream, causes any buffered data to be written to the file, and monitors cancellation requests.
public
void
Lock(long position,
long length)
position
The beginning of the range to lock. The value of this parameter must be equal to or greater than zero (0).
length
The range to be locked.
Prevents other processes from reading from or writing to the <see cref="T:System.IO.FileStream" /> .
public
int
Read(byte[] buffer,
int offset,
int count)
offset
The byte offset in <paramref name="array" /> at which the read bytes will be placed.
count
The maximum number of bytes to read.
Returns The total number of bytes read into the buffer. This might be less than the number of bytes requested if that number of bytes are not currently available, or zero if the end of the stream is reached.
Reads a block of bytes from the stream and writes the data in a given buffer.
public
Threading.Tasks.Task`1
ReadAsync(byte[] buffer,
int offset,
int count,
Threading.CancellationToken cancellationToken)
buffer
The buffer to write the data into.
offset
The byte offset in <paramref name="buffer" /> at which to begin writing data from the stream.
count
The maximum number of bytes to read.
cancellationToken
The token to monitor for cancellation requests.
Returns A task that represents the asynchronous read operation and wraps the total number of bytes read into the buffer. The result value can be less than the number of bytes requested if the number of bytes currently available is less than the requested number, or it can be 0 (zero) if the end of the stream has been reached.
Asynchronously reads a sequence of bytes from the current file stream and writes them to a byte array beginning at a specified offset, advances the position within the file stream by the number of bytes read, and monitors cancellation requests.
public
int
ReadByte() Returns The byte, cast to an <see cref="T:System.Int32" /> , or -1 if the end of the stream has been reached.
Reads a byte from the file and advances the read position one byte.
public
long
Seek(long offset,
SeekOrigin origin)
offset
The point relative to <paramref name="origin" /> from which to begin seeking.
origin
Specifies the beginning, the end, or the current position as a reference point for <paramref name="offset" /> , using a value of type <see cref="T:System.IO.SeekOrigin" /> .
Returns The new position in the stream.
Sets the current position of this stream to the given value.
public
void
SetLength(long value)
value
The new length of the stream.
Sets the length of this stream to the given value.
public
void
Unlock(long position,
long length)
position
The beginning of the range to unlock.
length
The range to be unlocked.
Allows access by other processes to all or part of a file that was previously locked.
public
void
Write(byte[] buffer,
int offset,
int count)
offset
The zero-based byte offset in <paramref name="array" /> from which to begin copying bytes to the stream.
count
The maximum number of bytes to write.
Writes a block of bytes to the file stream.
public
Threading.Tasks.Task
WriteAsync(byte[] buffer,
int offset,
int count,
Threading.CancellationToken cancellationToken)
buffer
The buffer to write data from.
offset
The zero-based byte offset in <paramref name="buffer" /> from which to begin copying bytes to the stream.
count
The maximum number of bytes to write.
cancellationToken
The token to monitor for cancellation requests.
Returns A task that represents the asynchronous write operation.
Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.
public
Threading.Tasks.ValueTask
WriteAsync(ReadOnlyMemory`1 buffer,
Threading.CancellationToken cancellationToken = null)
public
void
WriteByte(byte value)
value
A byte to write to the stream.
Writes a byte to the current position in the file stream.
Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. Instead of calling this method, ensure that the stream is properly disposed.
public
void
CopyTo(Stream destination)
Inherited from Stream
destination
The stream to which the contents of the current stream will be copied.
Reads the bytes from the current stream and writes them to another stream. Both streams positions are advanced by the number of bytes copied.
public
Threading.Tasks.Task
CopyToAsync(Stream destination)
Inherited from Stream
destination
The stream to which the contents of the current stream will be copied.
Returns A task that represents the asynchronous copy operation.
Asynchronously reads the bytes from the current stream and writes them to another stream. Both streams positions are advanced by the number of bytes copied.
public
Threading.Tasks.Task
CopyToAsync(Stream destination,
int bufferSize)
Inherited from Stream
destination
The stream to which the contents of the current stream will be copied.
bufferSize
The size, in bytes, of the buffer. This value must be greater than zero. The default size is 81920.
Returns A task that represents the asynchronous copy operation.
Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size. Both streams positions are advanced by the number of bytes copied.
public
Threading.Tasks.Task
CopyToAsync(Stream destination,
Threading.CancellationToken cancellationToken)
Inherited from Stream
destination
The stream to which the contents of the current stream will be copied.
cancellationToken
The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" /> .
Returns A task that represents the asynchronous copy operation.
Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified cancellation token. Both streams positions are advanced by the number of bytes copied.
protected
Threading.WaitHandle
CreateWaitHandle()
Inherited from Stream
Returns A reference to the allocated <see langword="WaitHandle" /> .
Allocates a <see cref="T:System.Threading.WaitHandle" /> object.
Releases all resources used by the <see cref="T:System.IO.Stream" /> .
public
Threading.Tasks.Task
FlushAsync()
Inherited from Stream
Returns A task that represents the asynchronous flush operation.
Asynchronously clears all buffers for this stream and causes any buffered data to be written to the underlying device.
Provides support for a <see cref="T:System.Diagnostics.Contracts.Contract" /> .
public
Threading.Tasks.Task`1
ReadAsync(byte[] buffer,
int offset,
int count)
Inherited from Stream
buffer
The buffer to write the data into.
offset
The byte offset in <paramref name="buffer" /> at which to begin writing data from the stream.
count
The maximum number of bytes to read.
Returns A task that represents the asynchronous read operation. The value of the <paramref name="TResult" /> parameter contains the total number of bytes read into the buffer. The result value can be less than the number of bytes requested if the number of bytes currently available is less than the requested number, or it can be 0 (zero) if <paramref name="count" /> is 0 or if the end of the stream has been reached.
Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.
public
int
ReadAtLeast(Span`1 buffer,
int minimumBytes,
bool throwOnEndOfStream = True)
Inherited from Stream
ReadAtLeastAsync(Memory`1 buffer,
int minimumBytes,
bool throwOnEndOfStream = True,
Threading.CancellationToken cancellationToken = null)
Inherited from Stream
public
void
ReadExactly(byte[] buffer,
int offset,
int count)
Inherited from Stream
buffer
An array of bytes. When this method returns, the buffer contains the specified byte array with the values between <paramref name="offset" /> and ( <paramref name="offset" /> + <paramref name="count" /> - 1) replaced by the bytes read from the current stream.
offset
The byte offset in <paramref name="buffer" /> at which to begin storing the data read from the current stream.
count
The number of bytes to be read from the current stream.
Reads <paramref name="count" /> number of bytes from the current stream and advances the position within the stream.
public
Threading.Tasks.ValueTask
ReadExactlyAsync(byte[] buffer,
int offset,
int count,
Threading.CancellationToken cancellationToken = null)
Inherited from Stream
buffer
The buffer to write the data into.
offset
The byte offset in <paramref name="buffer" /> at which to begin writing data from the stream.
count
The number of bytes to be read from the current stream.
cancellationToken
The token to monitor for cancellation requests.
Returns A task that represents the asynchronous read operation.
Asynchronously reads <paramref name="count" /> number of bytes from the current stream, advances the position within the stream, and monitors cancellation requests.
public
Threading.Tasks.ValueTask
ReadExactlyAsync(Memory`1 buffer,
Threading.CancellationToken cancellationToken = null)
Inherited from Stream
public
Threading.Tasks.Task
WriteAsync(byte[] buffer,
int offset,
int count)
Inherited from Stream
buffer
The buffer to write data from.
offset
The zero-based byte offset in <paramref name="buffer" /> from which to begin copying bytes to the stream.
count
The maximum number of bytes to write.
Returns A task that represents the asynchronous write operation.
Asynchronously writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.
public
object
GetLifetimeService()
Inherited from MarshalByRefObject
Returns An object of type <see cref="T:System.Runtime.Remoting.Lifetime.ILease" /> used to control the lifetime policy for this instance.
Retrieves the current lifetime service object that controls the lifetime policy for this instance.
public
object
InitializeLifetimeService()
Inherited from MarshalByRefObject
Returns An object of type <see cref="T:System.Runtime.Remoting.Lifetime.ILease" /> used to control the lifetime policy for this instance. This is the current lifetime service object for this instance if one exists; otherwise, a new lifetime service object initialized to the value of the <see cref="P:System.Runtime.Remoting.Lifetime.LifetimeServices.LeaseManagerPollTime" /> property.
Obtains a lifetime service object to control the lifetime policy for this instance.
protected
MarshalByRefObject
MemberwiseClone(bool cloneIdentity)
Inherited from MarshalByRefObject
cloneIdentity
<see langword="false" /> to delete the current <see cref="T:System.MarshalByRefObject" /> object's identity, which will cause the object to be assigned a new identity when it is marshaled across a remoting boundary. A value of <see langword="false" /> is usually appropriate. <see langword="true" /> to copy the current <see cref="T:System.MarshalByRefObject" /> object's identity to its clone, which will cause remoting client calls to be routed to the remote server object.
Returns A shallow copy of the current <see cref="T:System.MarshalByRefObject" /> object.
Creates a shallow copy of the current <see cref="T:System.MarshalByRefObject" /> object.
public
bool
Equals(object obj)
Inherited from object
obj
The object to compare with the current object.
Returns <see langword="true" /> if the specified object is equal to the current object; otherwise, <see langword="false" /> .
Determines whether the specified object is equal to the current object.
public
int
GetHashCode()
Inherited from object
Returns A hash code for the current object.
Serves as the default hash function.
public
Type
GetType()
Inherited from object
Returns The exact runtime type of the current instance.
Gets the <see cref="T:System.Type" /> of the current instance.
protected
object
MemberwiseClone()
Inherited from object
Returns A shallow copy of the current <see cref="T:System.Object" /> .
Creates a shallow copy of the current <see cref="T:System.Object" /> .
public
string
ToString()
Inherited from object
Returns A string that represents the current object.
Returns a string that represents the current object.