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FileOptions Enumeration

Represents additional options for creating a FileStream object.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

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

[SerializableAttribute]
[FlagsAttribute]
[ComVisibleAttribute(true)]
public enum FileOptions

Member nameDescription
NoneIndicates no additional parameters.
WriteThroughIndicates that the system should write through any intermediate cache and go directly to disk.
AsynchronousIndicates that a file can be used for asynchronous reading and writing.
RandomAccessIndicates that the file is accessed randomly. The system can use this as a hint to optimize file caching.
DeleteOnCloseIndicates that a file is automatically deleted when it is no longer in use.
SequentialScanIndicates that the file is to be accessed sequentially from beginning to end. The system can use this as a hint to optimize file caching. If an application moves the file pointer for random access, optimum caching may not occur; however, correct operation is still guaranteed.

Specifying this flag can increase performance for applications that read large files using sequential access. Performance gains can be even more noticeable for applications that read large files mostly sequentially, but occasionally skip over small ranges of bytes.

EncryptedIndicates that a file is encrypted and can be decrypted only by using the same user account used for encryption.

Use the FileOptions enumeration to specify advanced file options.

The following code example writes data to a file and then reads the data using the FileStream object.


using System;
using System.IO;
using System.Text;
using System.Security.AccessControl;

namespace FileSystemExample
{
    class FileStreamExample
    {
        public static void Main()
        {
            try
            {
                // Create a file and write data to it.

                // Create an array of bytes.
                byte[] messageByte = Encoding.ASCII.GetBytes("Here is some data.");

                // Specify an access control list (ACL)
                FileSecurity fs = new FileSecurity();

                fs.AddAccessRule(new FileSystemAccessRule(@"DOMAINNAME\AccountName",
                                                            FileSystemRights.ReadData,
                                                            AccessControlType.Allow));

                // Create a file using the FileStream class.
                FileStream fWrite = new FileStream("test.txt", FileMode.Create, FileSystemRights.Modify, FileShare.None, 8, FileOptions.None, fs);

                // Write the number of bytes to the file.
                fWrite.WriteByte((byte)messageByte.Length);

                // Write the bytes to the file.
                fWrite.Write(messageByte, 0, messageByte.Length);

                // Close the stream.
                fWrite.Close();


                // Open a file and read the number of bytes.

                FileStream fRead = new FileStream("test.txt", FileMode.Open);

                // The first byte is the string length.
                int length = (int)fRead.ReadByte();

                // Create a new byte array for the data.
                byte[] readBytes = new byte[length];

                // Read the data from the file.
                fRead.Read(readBytes, 0, readBytes.Length);

                // Close the stream.
                fRead.Close();

                // Display the data.
                Console.WriteLine(Encoding.ASCII.GetString(readBytes));

                Console.WriteLine("Done writing and reading data.");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }

            Console.ReadLine();
        }
    }
}



.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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