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Tools Used: Visual C#.NET The FileStream class is derived from Stream class. This class can be used for reading from and writing to files such as bytes, characters, strings, and other data-type values to a file. Most stock quote data provided by BATS. Market indices are shown in real time, except for the DJIA, which is delayed by two minutes. All times are ET. FileStream Read File [C#] This example shows how to safely read file using FileStream in C#. To be sure the whole file is correctly read, you should call FileStream.Read method in a loop, even if in the most cases the whole file is read in a single call of FileStream.Read method.
Important This type implements the interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its method in a try/ catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the 'Using an Object that Implements IDisposable' section in the interface topic.
The property detects whether the file handle was opened asynchronously. You specify this value when you create an instance of the class using a constructor that has an isAsync, useAsync, or options parameter. When the property is true, the stream utilizes overlapped I/O to perform file operations asynchronously. However, the property does not have to be true to call the, or method. When the property is false and you call the asynchronous read and write operations, the UI thread is still not blocked, but the actual I/O operation is performed synchronously.
The method supports random access to files. Allows the read/write position to be moved to any position within the file. This is done with byte offset reference point parameters. The byte offset is relative to the seek reference point, which can be the beginning, the current position, or the end of the underlying file, as represented by the three members of the enumeration. Note Disk files always support random access. At the time of construction, the property value is set to true or false depending on the underlying file type.If the underlying file type is FILETYPEDISK, as defined in winbase.h, the property value is true. Otherwise, the property value is false.
If a process terminates with part of a file locked or closes a file that has outstanding locks, the behavior is undefined. For directory operations and other file operations, see the, and classes. The class is a utility class that has static methods primarily for the creation of objects based on file paths. The class creates a stream from a byte array and is similar to the class. For a list of common file and directory operations, see.
Detection of Stream Position Changes When a object does not have an exclusive hold on its handle, another thread could access the file handle concurrently and change the position of the operating system's file pointer that is associated with the file handle. In this case, the cached position in the object and the cached data in the buffer could be compromised. The object routinely performs checks on methods that access the cached buffer to ensure that the operating system's handle position is the same as the cached position used by the object. If an unexpected change in the handle position is detected in a call to the method, the.NET Framework discards the contents of the buffer and reads the stream from the file again.
This can affect performance, depending on the size of the file and any other processes that could affect the position of the file stream. If an unexpected change in the handle position is detected in a call to the method, the contents of the buffer are discarded and an exception is thrown.
A object will not have an exclusive hold on its handle when either the property is accessed to expose the handle or the object is given the property in its constructor. Constructors Initializes a new instance of the class for the specified file handle, with the specified read/write permission.
Initializes a new instance of the class for the specified file handle, with the specified read/write permission and FileStream instance ownership. Initializes a new instance of the class for the specified file handle, with the specified read/write permission, FileStream instance ownership, and buffer size. Initializes a new instance of the class for the specified file handle, with the specified read/write permission, FileStream instance ownership, buffer size, and synchronous or asynchronous state. Initializes a new instance of the class for the specified file handle, with the specified read/write permission. Initializes a new instance of the class for the specified file handle, with the specified read/write permission, and buffer size.
Initializes a new instance of the class for the specified file handle, with the specified read/write permission, buffer size, and synchronous or asynchronous state. Initializes a new instance of the class with the specified path and creation mode. Initializes a new instance of the class with the specified path, creation mode, and read/write permission.
Initializes a new instance of the class with the specified path, creation mode, read/write permission, and sharing permission. Initializes a new instance of the class with the specified path, creation mode, read/write and sharing permission, and buffer size. Initializes a new instance of the class with the specified path, creation mode, read/write and sharing permission, buffer size, and synchronous or asynchronous state. Initializes a new instance of the class with the specified path, creation mode, read/write and sharing permission, the access other FileStreams can have to the same file, the buffer size, and additional file options.
Initializes a new instance of the class with the specified path, creation mode, access rights and sharing permission, the buffer size, and additional file options. Initializes a new instance of the class with the specified path, creation mode, access rights and sharing permission, the buffer size, additional file options, access control and audit security. Properties Gets a value that indicates whether the current stream supports reading. Gets a value that indicates whether the current stream supports seeking. Gets a value that determines whether the current stream can time out. (Inherited from ) Gets a value that indicates whether the current stream supports writing. Gets the operating system file handle for the file that the current FileStream object encapsulates.
Gets a value that indicates whether the FileStream was opened asynchronously or synchronously. Gets the length in bytes of the stream. Gets the absolute path of the file opened in the FileStream. Gets or sets the current position of this stream. Gets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out. (Inherited from ) Gets a object that represents the operating system file handle for the file that the current object encapsulates. Gets or sets a value, in miliseconds, that determines how long the stream will attempt to write before timing out.
(Inherited from ) Methods Begins an asynchronous read operation. Consider using instead. Begins an asynchronous write operation. Consider using instead. This member overrides, and more complete documentation might be available in that topic. Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. Reads the bytes from the current stream and writes them to another stream.
(Inherited from ) Reads the bytes from the current stream and writes them to another stream, using a specified buffer size. (Inherited from ) Asynchronously reads the bytes from the current stream and writes them to another stream. (Inherited from ) Inherited from Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size. (Inherited from ) Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size and cancellation token.
(Inherited from ) Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from ) Allocates a object. (Inherited from ) Releases all resources used by the. (Inherited from ) Releases the unmanaged resources used by the and optionally releases the managed resources.
Waits for the pending asynchronous read operation to complete. (Consider using instead.) Ends an asynchronous write operation and blocks until the I/O operation is complete. (Consider using instead.) Determines whether the specified object is equal to the current object.
(Inherited from ) Ensures that resources are freed and other cleanup operations are performed when the garbage collector reclaims the FileStream. Clears buffers for this stream and causes any buffered data to be written to the file. Clears buffers for this stream and causes any buffered data to be written to the file, and also clears all intermediate file buffers. Asynchronously clears all buffers for this stream and causes any buffered data to be written to the underlying device. (Inherited from ) Asynchronously clears all buffers for this stream, causes any buffered data to be written to the underlying device, and monitors cancellation requests. Gets a object that encapsulates the access control list (ACL) entries for the file described by the current object. Serves as the default hash function.
(Inherited from ) Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from ) Gets the of the current instance. (Inherited from ) Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from ) Prevents other processes from reading from or writing to the. Creates a shallow copy of the current. (Inherited from ) Creates a shallow copy of the current object. (Inherited from ) Provides support for a.
(Inherited from ) Reads a block of bytes from the stream and writes the data in a given buffer. Inherited from Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read. (Inherited from ) Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests. Inherited from Reads a byte from the file and advances the read position one byte. Sets the current position of this stream to the given value. Applies access control list (ACL) entries described by a object to the file described by the current object. Sets the length of this stream to the given value.
Returns a string that represents the current object. (Inherited from ) Allows access by other processes to all or part of a file that was previously locked. Writes a block of bytes to the file stream. Inherited from Asynchronously writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written. (Inherited from ) 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. Inherited from Writes a byte to the current position in the file stream.
C# Filestream Write Example
Explicit Interface Implementations Releases all resources used by the. (Inherited from ) Extension Methods Applies to See also. Feedback.