System.IO.FileInfo Class

Summary

Provides instance methods for the creation, copying, deletion, moving, and opening of files, and aids in the creation of FileStream objects.

C# Syntax:

[Serializable] public sealed class FileInfo : FileSystemInfo

All methods of the File class are static and can therefore be called without having an instance of a file. The FileInfo class contains only instance methods. The static methods of the File class perform security checks on all methods. If you are going to reuse an object several times, consider using the corresponding instance method of FileInfo instead, because the security check will not always be necessary.

Note In members that accept a path as an input string, that path must be well-formed or an exception is raised. For example, if a path is fully qualified but begins with a space, the path is not trimmed in methods of the class. Therefore, the path is malformed and an exception is raised. Similarly, a path or a combination of paths cannot be fully qualified twice. For example, "c:\temp c:\windows" also raises an exception in most cases. Ensure that your paths are well-formed when using methods that accept a path string.

In members that accept a path, the path can refer to a file or just a directory. The specified path can also refer to a relative path or a Universal Naming Convention (UNC) path for a server and share name. For example, all of the following are acceptable paths:

• "c:\\MyDir\\MyFile.txt" in C#, or "c:\MyDir\MyFile.txt" in Visual Basic. (Visual Basic not implemented in the shared source CLI)
• "c:\\MyDir" in C#, or "c:\MyDir" in Visual Basic. (Visual Basic not implemented in the shared source CLI)
• "MyDir\\MySubdir" in C#, or "MyDir\MySubDir" in Visual Basic. (Visual Basic not implemented in the shared source CLI)
• "\\\\MyServer\\MyShare" in C#, or "\\MyServer\MyShare" in Visual Basic. (Visual Basic not implemented in the shared source CLI)

By default, full read/write access to new files is granted to all users.

System.IO Namespace

System.IO.FileInfo Member List:

Public Constructors

ctor #1

Initializes a new instance of the FileInfo class, which acts as a wrapper for a file path.

Public Properties

Attributes (inherited from System.IO.FileSystemInfo)	Read-write See base class member description: System.IO.FileSystemInfo.Attributes Gets or sets the FileAttributes of the current FileSystemInfo.
CreationTime (inherited from System.IO.FileSystemInfo)	Read-write See base class member description: System.IO.FileSystemInfo.CreationTime Gets or sets the creation time of the current FileSystemInfo object.
Directory	Read-only Gets an instance of the parent directory.
DirectoryName	Read-only Gets a string representing the directory's full path.
Exists	Read-only Overridden: Gets a value indicating whether a file exists.
Extension (inherited from System.IO.FileSystemInfo)	Read-only See base class member description: System.IO.FileSystemInfo.Extension Gets the string representing the extension part of the file.
FullName (inherited from System.IO.FileSystemInfo)	Read-only See base class member description: System.IO.FileSystemInfo.FullName Gets the full path of the directory or file.
LastAccessTime (inherited from System.IO.FileSystemInfo)	Read-write See base class member description: System.IO.FileSystemInfo.LastAccessTime Gets or sets the time the current file or directory was last accessed.
LastWriteTime (inherited from System.IO.FileSystemInfo)	Read-write See base class member description: System.IO.FileSystemInfo.LastWriteTime Gets or sets the time when the current file or directory was last written to.
Length	Read-only Gets the size of the current file or directory.
Name	Read-only Overridden: Gets the name of the file.

Public Methods

AppendText	Creates a StreamWriter that appends text to the file represented by this instance of the FileInfo.
CopyTo	Overloaded: CopyTo(string destFileName) Copies an existing file to a new file, disallowing the overwriting of an existing file.
CopyTo	Overloaded: CopyTo(string destFileName, bool overwrite) Copies an existing file to a new file, allowing the overwriting of an existing file.
Create	Creates a file.
CreateObjRef (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.CreateObjRef Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
CreateText	Creates a StreamWriter that writes a new text file.
Delete	Overridden: Permanently deletes a file.
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.GetLifetimeService Retrieves the current lifetime service object that controls the lifetime policy for this instance.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
InitializeLifetimeService (inherited from System.MarshalByRefObject)	See base class member description: System.MarshalByRefObject.InitializeLifetimeService Obtains a lifetime service object to control the lifetime policy for this instance.
MoveTo	Moves a specified file to a new location, providing the option to specify a new file name.
Open	Overloaded: Open(FileMode mode) Opens a file in the specified mode.
Open	Overloaded: Open(FileMode mode, FileAccess access) Opens a file in the specified mode with read, write, or read/write access.
Open	Overloaded: Open(FileMode mode, FileAccess access, FileShare share) Opens a file in the specified mode with read, write, or read/write access and the specified sharing option.
OpenRead	Creates a read-only FileStream.
OpenText	Creates a StreamReader with UTF8 encoding that reads from an existing text file.
OpenWrite	Creates a write-only FileStream.
Refresh (inherited from System.IO.FileSystemInfo)	See base class member description: System.IO.FileSystemInfo.Refresh Refreshes the state of the object.
ToString	Overridden: Returns the fully qualified path as a string.

Protected Fields

FullPath (inherited from System.IO.FileSystemInfo)	See base class member description: System.IO.FileSystemInfo.FullPath Represents the fully qualified path of the directory or file.
OriginalPath (inherited from System.IO.FileSystemInfo)	See base class member description: System.IO.FileSystemInfo.OriginalPath The path originally specified by the user, whether relative or absolute.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.MarshalByRefObject
• System.IO.FileSystemInfo
• System.IO.FileInfo

System.IO.FileInfo Member Details

Summary

Initializes a new instance of the FileInfo class, which acts as a wrapper for a file path.

C# Syntax:

public FileInfo(    string fileName );

fileName

The fully qualified name of the new file, or the relative file name.

Exceptions

Exception Type	Condition
ArgumentNullException	fileName is null.
SecurityException	The caller does not have the required permission.
ArgumentException	The file name is empty, contains only white spaces, or contains invalid characters.
UnauthorizedAccessException	Access to fileName is denied.
PathTooLongException	The specified path, file name, or both are too long. After full qualification, each must contain fewer than 256 characters.
NotSupportedException	fileName contains a colon (:) in the middle of the string.

You can specify either the fully qualified or the relative file name, but the security check gets the fully qualified name.

using System;
using System.IO;

public class FileInfoMainTest {
    public static void Main() {

        // either open an existing file, or create a new one
        FileInfo fi = new FileInfo("temp.txt");

        // create a writer, ready to add entries to the file
        StreamWriter sw = fi.AppendText();

        sw.WriteLine("This is a new entry to add to the file");
        sw.WriteLine("This is yet another line to add...");
        sw.Flush();
        sw.Close();

        // get the information out of the file, and print it to screen
        StreamReader sr = new StreamReader( fi.OpenRead() );

        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );
    }
}

    

FileIOPermission for reading files. Associated enumeration: FileIOPermissionAccess.Read

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Inherited
See base class member description: System.IO.FileSystemInfo.FullPath

Summary

Represents the fully qualified path of the directory or file.

C# Syntax:

protected string FullPath;

Notes to inheritors: Classes derived from FileSystemInfo can use the FullPath field to determine the full path of the object being manipulated.

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Inherited
See base class member description: System.IO.FileSystemInfo.OriginalPath

Summary

The path originally specified by the user, whether relative or absolute.

C# Syntax:

protected string OriginalPath;

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Inherited
See base class member description: System.IO.FileSystemInfo.Attributes

Summary

Gets or sets the FileAttributes of the current FileSystemInfo.

C# Syntax:

public FileAttributes Attributes {get; set;}

Exceptions

Exception Type	Condition
FileNotFoundException	The caller attempts to access a file that does not exist on disk.
SecurityException	The caller does not have the required permission.
ArgumentException	The caller attempts to set an invalid file attribute.
IOException	FileSystemInfo.Refresh cannot initialize the data.

The value of this property is a combination of the archive, compressed, directory, hidden, offline, read-only, system, and temporary file attribute flags.

FileIOPermissionAccess Write permission required to set the attributes for the specified file.

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Inherited
See base class member description: System.IO.FileSystemInfo.CreationTime

Summary

Gets or sets the creation time of the current FileSystemInfo object.

C# Syntax:

public DateTime CreationTime {get; set;}

Exceptions

Exception Type	Condition
IOException	FileSystemInfo.Refresh cannot initialize the data.
FileNotFoundException	The FileSystemInfo object does not exist.

This property value is null if the file system containing the FileSystemInfo object does not support this information.

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Summary

Gets an instance of the parent directory.

C# Syntax:

public DirectoryInfo Directory {get;}

Exceptions

Exception Type	Condition
DirectoryNotFoundException	The specified file does not exist.
SecurityException	The caller does not have the required permission.

To get the parent directory as a string, use the FileInfo.DirectoryName property.

using System;
using System.IO;

public class DirectoryTest {
    public static void Main() {

        // open an existing file, or create a new one
        FileInfo fi = new FileInfo("temp.txt");

        // determine the full path of the file just created...
        DirectoryInfo di = fi.Directory;

        // figure out what other entries are in that directory
        FileSystemInfo[] fsi = di.GetFileSystemInfos();

        Console.WriteLine("The directory '{0}' contains the following files and directories:", di.FullName);

        // print the names of all the files and subdirectories of that directory
        foreach (FileSystemInfo info in fsi)
            Console.WriteLine(info.Name);
    }
}

    

FileIOPermission for reading files. Associated enumeration: FileIOPermissionAccess.Read

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Summary

Gets a string representing the directory's full path.

C# Syntax:

public string DirectoryName {get;}

Exceptions

Exception Type	Condition
SecurityException	The caller does not have the required permission.
ArgumentNullException	null was passed in for the directory name.

To get the parent directory as a DirectoryInfo object, use the FileInfo.Directory property.

        string   fileName = "C:\\autoexec.bat";
        FileInfo fileInfo = new FileInfo(fileName);
        if (!fileInfo.Exists) {
            return;
        }

        Console.WriteLine("{0} has a directoryName of {1}", 
                          fileName, fileInfo.DirectoryName);

    

FileIOPermission for reading files. Associated enumeration: FileIOPermissionAccess.PathDiscovery

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Summary

Gets a value indicating whether a file exists.

C# Syntax:

public override bool Exists {get;}

using System;
using System.IO;

public class ExistsTest {
    public static void Main() {

        string neFile = "nonexistentfile";

        // open an existing file, or create a new one
        FileInfo fi = new FileInfo(neFile);

        DetermineExists(fi, neFile);

        neFile = "newFile.txt";

        // create a file, so it exists
        fi = new FileInfo(neFile);
        FileStream fs = fi.Create();

        DetermineExists(fi, neFile);

        // close the file so it can be deleted
        fs.Close();

        // delete the file
        try {
            fi.Delete();
            Console.WriteLine("The file '{0}' was deleted successfully", fi.Name);
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void DetermineExists( FileInfo fi, string fileName ) {

        // figure out if the file exists or not
        if (fi.Exists)
            Console.WriteLine("The file '{0}' exists in the specified directory", fileName);
        else
            Console.WriteLine("The file '{0}' does not exist in the specified directory", fileName);
    }
}

    

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Inherited
See base class member description: System.IO.FileSystemInfo.Extension

Summary

Gets the string representing the extension part of the file.

C# Syntax:

public string Extension {get;}

The Extension property returns the FileSystemInfo extension, including the period (.). For example, for a file c:\NewFile.txt, this property returns ".txt".

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Inherited
See base class member description: System.IO.FileSystemInfo.FullName

Summary

Gets the full path of the directory or file.

C# Syntax:

public virtual string FullName {get;}

For example, for a file c:\NewFile.txt, this property returns "NewFile.txt".

FileIOPermission for access to the path. Associated enumeration: FileIOPermissionAccess.PathDiscovery

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Inherited
See base class member description: System.IO.FileSystemInfo.LastAccessTime

Summary

Gets or sets the time the current file or directory was last accessed.

C# Syntax:

public DateTime LastAccessTime {get; set;}

Exceptions

Exception Type	Condition
IOException	FileSystemInfo.Refresh cannot initialize the data.

This property value is null if the file system containing the file does not support this information.

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Inherited
See base class member description: System.IO.FileSystemInfo.LastWriteTime

Summary

Gets or sets the time when the current file or directory was last written to.

C# Syntax:

public DateTime LastWriteTime {get; set;}

Exceptions

Exception Type	Condition
IOException	FileSystemInfo.Refresh cannot initialize the data.

This property value is null if the file system containing the file does not support this information.

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Summary

Gets the size of the current file or directory.

C# Syntax:

public long Length {get;}

Exceptions

Exception Type	Condition
IOException	FileSystemInfo.Refresh cannot update the state of the file or directory.
FileNotFoundException	The file does not exist.

This property value is null if the file system containing the file does not support this information.

        string        dirName = "C:\\";
        DirectoryInfo dirInfo = new DirectoryInfo(dirName);

        Console.WriteLine("{0} contains the following files:", dirName);
        Console.WriteLine("Size\t Filename");
        foreach (FileInfo fileInfo in dirInfo.GetFiles()) {
            try { 
                Console.WriteLine("{0}\t {1}", 
                                  fileInfo.Length, fileInfo.Name);
            }
            catch (IOException e) {
                Console.WriteLine("\t {0}: {1}", fileInfo.Name, e.Message);
            }
        }

    

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Summary

Gets the name of the file.

C# Syntax:

public override string Name {get;}

using System;
using System.IO;

public class NameTest {
    public static void Main() {

        // create a reference to the current directory
        DirectoryInfo di = new DirectoryInfo(Environment.CurrentDirectory);

        // create an array representing the files in the current directory
        FileInfo[] fi = di.GetFiles();

        Console.WriteLine("The following files exist in the current directory:");

        // print out the names of those files
        foreach (FileInfo fiTemp in fi)
            Console.WriteLine(fiTemp.Name);
    }
}

    

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Summary

Creates a StreamWriter that appends text to the file represented by this instance of the FileInfo.

C# Syntax:

public StreamWriter AppendText();

Return Value:

A new StreamWriter.

using System;
using System.IO;

public class AppendTextTest {
    public static void Main() {

        // create a reference to a file, which may or may not exist
        // if it doesn't exist, it is not yet created
        FileInfo fi = new FileInfo("temp.txt");

        // create a writer, ready to add entries to the file
        StreamWriter sw = fi.AppendText();

        sw.WriteLine("Add as many lines as you like...");
        sw.WriteLine("Add another line to the output...");
        sw.Flush();
        sw.Close();

        // get the information out of the file, and print it to screen,
        // remember that the file may have other lines, if it already existed
        StreamReader sr = new StreamReader( fi.OpenRead() );

        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );
    }
}

    

FileIOPermission for reading and appending to files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Append

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Summary

Copies an existing file to a new file, disallowing the overwriting of an existing file.

C# Syntax:

public FileInfo CopyTo(    string destFileName );

destFileName

The name of the new file to copy to.

Return Value:

A new file with a fully qualified path.

Exceptions

Exception Type	Condition
ArgumentException	destFileName is empty, contains only white spaces, or contains invalid characters.
IOException	An error occurs, or the destination file already exists.
SecurityException	The caller does not have the required permission.
ArgumentNullException	destFileName is null.
UnauthorizedAccessException	A directory path is passed in, or the file is being moved to a different drive.
PathTooLongException	The specified path, file name, or both are too long. After full qualification, each must contain fewer than 256 characters.
NotSupportedException	destFileName contains a colon (:) in the middle of the string.

Use the CopyTo(String, Boolean) method to allow overwriting of an existing file.

using System;
using System.IO;

public class CopyToTest {
    public static void Main() {

        // create a reference to a file, which may or may not exist
        // if it doesn't exist, it is not yet created
        FileInfo fi = new FileInfo("temp.txt");

        // create a writer, ready to add entries to the file
        StreamWriter sw = fi.AppendText();

        sw.WriteLine("Add as many lines as you like...");
        sw.WriteLine("Add another line to the output...");
        sw.Flush();
        sw.Close();

        // get the information out of the file, and print it to screen
        StreamReader sr = new StreamReader( fi.OpenRead() );

        Console.WriteLine("This is the information in the first file:");
        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );

        // copy this file to ANOTHER file. The true parameter indicates
        // to overwrite the file if it already exists
        FileInfo newfi = fi.CopyTo("newTemp.txt", true);

        // get the information out of the new file, and print it to screen
        sr = new StreamReader( newfi.OpenRead() );

        Console.WriteLine("{0}This is the information in the second file:", Environment.NewLine);
        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );
    }
}

    

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Summary

Copies an existing file to a new file, allowing the overwriting of an existing file.

C# Syntax:

public FileInfo CopyTo(    string destFileName,    bool overwrite );

destFileName

The name of the new file to copy to.

overwrite

true to allow an existing file to be overwritten; otherwise, false.

Return Value:

A new file, or an overwrite of an existing file if overwrite is true. If the file exists and overwrite is false, an IOException is thrown.

Exceptions

Exception Type	Condition
ArgumentException	destFileName is empty, contains only white spaces, or contains invalid characters.
IOException	An error occurs, or the destination file already exists and overwrite is false.
SecurityException	The caller does not have the required permission.
ArgumentNullException	destFileName is null.
UnauthorizedAccessException	A directory path is passed in, or the file is being moved to a different drive.
PathTooLongException	The specified path, file name, or both are too long. After full qualification, each must contain fewer than 256 characters.
NotSupportedException	destFileName contains a colon (:) in the middle of the string.

Use this method to allow or prevent overwriting of an existing file. Use the CopyTo(String) method to prevent overwriting of an existing file by default.

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Summary

Creates a file.

C# Syntax:

public FileStream Create();

Return Value:

A new file.

By default, full read/write access to new files is granted to all users.

This method provides a convenient, instantiated wrapper for the functionality provided by File.Create.

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Inherited
See base class member description: System.MarshalByRefObject.CreateObjRef

Summary

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

C# Syntax:

public virtual ObjRef CreateObjRef(    Type requestedType );

requestedType

The Type of the object that the new ObjRef will reference.

Return Value:

Information required to generate a proxy.

Exceptions

Exception Type	Condition
RemotingException	This instance is not a valid remoting object.

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Summary

Creates a StreamWriter that writes a new text file.

C# Syntax:

public StreamWriter CreateText();

Return Value:

A new StreamWriter.

Exceptions

Exception Type	Condition
UnauthorizedAccessException	The file name is a directory.
IOException	The disk is read-only.
SecurityException	The caller does not have the required permission.

By default, full read/write access to new files is granted to all users.

        FileInfo  fileInfo = new FileInfo("myFile");
        
        // Create the file and output some text to it.
        StreamWriter s = fileInfo.CreateText();
        s.WriteLine("Output to the file");
        s.Close();

        fileInfo.Refresh();
        Console.WriteLine("File '{0}' now has size {1} bytes", 
                          fileInfo.Name, fileInfo.Length);

    

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Summary

Permanently deletes a file.

C# Syntax:

public override void Delete();

Exceptions

Exception Type	Condition
IOException	The target file is open or memory-mapped on a computer running Microsoft Windows NT.
SecurityException	The caller does not have the required permission.
UnauthorizedAccessException	The path is a directory.

If the file does not exist, this method does nothing.

using System;
using System.IO;

public class DeleteTest {
    public static void Main() {

        // create a reference to a file
        FileInfo fi = new FileInfo("temp.txt");

        // actually create the file
        FileStream fs = fi.Create();

        // modify the file as required
        // ...

        // close the file
        fs.Close();

        // delete the file
        fi.Delete();
    }
}

    

FileIOPermission for reading and writing files. Associated enumeration: FileIOPermissionAccess.Write

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Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~FileInfo();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.Object.GetHashCode

C# Syntax:

public virtual int GetHashCode();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.MarshalByRefObject.GetLifetimeService

Summary

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

C# Syntax:

public object GetLifetimeService();

Return Value:

An object of type ILease used to control the lifetime policy for this instance.

For more information about lifetime services, see the LifetimeServices class.

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Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

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Inherited
See base class member description: System.MarshalByRefObject.InitializeLifetimeService

Summary

Obtains a lifetime service object to control the lifetime policy for this instance.

C# Syntax:

public virtual object InitializeLifetimeService();

Return Value:

An object of type 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 LifetimeServices.LeaseManagerPollTime property.

For more information about lifetime services, see the LifetimeServices class.

The following code example demonstrates creating a lease.

 public class MyClass : MarshalByRefObject
 {
   public override Object InitializeLifetimeService()
   {
     ILease lease = (ILease)base.InitializeLifetimeService();
     if (lease.CurrentState == LeaseState.Initial)
     {
          lease.InitialLeaseTime = TimeSpan.FromMinutes(1);
          lease.SponsorshipTimeout = TimeSpan.FromMinutes(2);
           lease.RenewOnCallTime = TimeSpan.FromSeconds(2);
     }
       return lease;
   }
 }

    

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Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

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Summary

Moves a specified file to a new location, providing the option to specify a new file name.

C# Syntax:

public void MoveTo(    string destFileName );

destFileName

The path to move the file to, which can specify a different file name.

Exceptions

Exception Type	Condition
IOException	An I/O error occurs, such as the destination file already exists or the destination device is not ready.
ArgumentNullException	destFileName is null.
ArgumentException	destFileName is empty, contains only white spaces, or contains invalid characters.
SecurityException	The caller does not have the required permission.
UnauthorizedAccessException	destFileName is read-only or a directory.
FileNotFoundException	The file is not found.
DirectoryNotFoundException	The path specified in destFileName cannot be found.
PathTooLongException	The specified path, file name, or both are too long. After full qualification, each must contain fewer than 256 characters.
NotSupportedException	destFileName contains a colon (:) in the middle of the string.

This method works across disk volumes. For example, the file c:\MyFile.txt can be moved to d:\public and renamed NewFile.txt.

using System;
using System.IO;

public class MoveToTest {
    public static void Main() {

        // create a reference to a file, which may or may not exist
        // if it doesn't exist, it is not yet created
        FileInfo fi = new FileInfo("temp.txt");

        // create a writer, ready to add entries to the file
        StreamWriter sw = fi.AppendText();

        sw.WriteLine("Add as many lines as you like...");
        sw.WriteLine("Add another line to the output...");
        sw.Flush();
        sw.Close();

        // ensure the target file doesn't exist, since this is disallowed...
        if (File.Exists("newTemp.txt"))
            File.Delete("newTemp.txt");

        // move this file to ANOTHER file.
        fi.MoveTo("newTemp.txt");

        // get the information out of the new file, and print it to screen
        StreamReader sr = new StreamReader( fi.OpenRead() );

        Console.WriteLine("{0}This is the information in the new file, '{1}':", Environment.NewLine, fi.Name);
        while (sr.Peek() != -1)
            Console.WriteLine( sr.ReadLine() );
    }
}

    

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Summary

Opens a file in the specified mode.

C# Syntax:

public FileStream Open(    FileMode mode );

mode

A FileMode constant specifying the mode (for example, Open or Append) in which to open the file.

Return Value:

A file opened in the specified mode, with read/write access and unshared.

Exceptions

Exception Type	Condition
FileNotFoundException	The file is not found.
UnauthorizedAccessException	The file is read-only or a directory.
DirectoryNotFoundException	The directory is not found.
IOException	The file is already open.

FileIOPermission for writing to and reading from files. Associated enumerations: FileIOPermissionAccess.Write and FileIOPermissionAccess.Read

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Summary

Opens a file in the specified mode with read, write, or read/write access.

C# Syntax:

public FileStream Open(    FileMode mode,    FileAccess access );

mode

A FileMode constant specifying the mode (for example, Open or Append) in which to open the file.

access

A FileAccess constant specifying whether to open the file with Read, Write, or ReadWrite file access.

Return Value:

A FileStream object opened in the specified mode and access, and unshared.

Exceptions

Exception Type	Condition
SecurityException	The caller does not have the required permission.
ArgumentException	path is empty or contains only white spaces.
FileNotFoundException	The file is not found.
ArgumentNullException	One or more arguments is null.
UnauthorizedAccessException	path is read-only or a directory.
DirectoryNotFoundException	The directory is not found.
IOException	The file is already open.

FileIOPermission for writing to and reading from files. Associated enumerations: FileIOPermissionAccess.Write and FileIOPermissionAccess.Read

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Summary

Opens a file in the specified mode with read, write, or read/write access and the specified sharing option.

C# Syntax:

public FileStream Open(    FileMode mode,    FileAccess access,    FileShare share );

mode

A FileMode constant specifying the mode (for example, Open or Append) in which to open the file.

access

A FileAccess constant specifying whether to open the file with Read, Write, or ReadWrite file access.

share

A FileShare constant specifying the type of access other FileStream objects have to this file.

Return Value:

A FileStream object opened with the specified mode, access, and sharing options.

Exceptions

Exception Type	Condition
SecurityException	The caller does not have the required permission.
ArgumentException	path is empty or contains only white spaces.
FileNotFoundException	The file is not found.
ArgumentNullException	One or more arguments is null.
UnauthorizedAccessException	path is read-only or a directory.
DirectoryNotFoundException	The directory is not found.
IOException	The file is already open.

using System;
using System.IO;

public class OpenTest {
    public static void Main() {

        // open an existing file, or create a new one
        FileInfo fi = new FileInfo("temp.txt");

        // Open the file just specified. Open it so that no-one else can use it
        FileStream fs = fi.Open( FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None );

        // create another reference to the same file
        FileInfo nextfi = new FileInfo("temp.txt");        

        try {
            // try opening the same file, which is locked by the previous process
            nextfi.Open( FileMode.OpenOrCreate, FileAccess.Read );

            Console.WriteLine("The file was not locked, and was opened by a second process");
        } catch (IOException) {
            Console.WriteLine("The file could not be opened because it was locked by another process");
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }

        // close the file so it can be deleted
        fs.Close();
    }
}

    

FileIOPermission for writing to and reading from files. Associated enumerations: FileIOPermissionAccess.Write and FileIOPermissionAccess.Read

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Summary

Creates a read-only FileStream.

C# Syntax:

public FileStream OpenRead();

Return Value:

A new read-only FileStream object.

Exceptions

Exception Type	Condition
UnauthorizedAccessException	path is read-only or a directory.
DirectoryNotFoundException	The directory is not found.
IOException	The file is already open.

        // Create a temporary file.
        string      fileName = Path.GetTempFileName();
        FileInfo    fileInfo = new FileInfo(fileName);

        // Write the current time to the file in binary form.
        DateTime   currentTime = DateTime.Now;
        FileStream fileWriteStream = fileInfo.OpenWrite();
        BinaryFormatter binaryFormatter = new BinaryFormatter();
        binaryFormatter.Serialize(fileWriteStream, currentTime);
        fileWriteStream.Close();

        // Read the time back from the file.
        FileStream fileReadStream = fileInfo.OpenRead();
        DateTime   timeRead = (DateTime)binaryFormatter.Deserialize(fileReadStream);
        fileReadStream.Close();

        Console.WriteLine("Value written {0}", currentTime);
        Console.WriteLine("Value read    {0}", timeRead);

    

FileIOPermission for reading files. Associated enumeration: FileIOPermissionAccess.Read

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Summary

Creates a StreamReader with UTF8 encoding that reads from an existing text file.

C# Syntax:

public StreamReader OpenText();

Return Value:

A new StreamReader with UTF8 encoding.

Exceptions

Exception Type	Condition
SecurityException	The caller does not have the required permission.
FileNotFoundException	The file is not found.
UnauthorizedAccessException	path is read-only or a directory.
DirectoryNotFoundException	The directory is not found.

        string    fileName = Path.GetTempFileName();
        FileInfo  fileInfo = new FileInfo(fileName);
        Console.WriteLine("File '{0}' created of size {1} bytes", 
                          fileName, fileInfo.Length);
        
        // Append some text to the file.
        StreamWriter s = fileInfo.AppendText();
        s.WriteLine("The text in the file");
        s.Close();

        fileInfo.Refresh();
        Console.WriteLine("File '{0}' now has size {1} bytes", 
                          fileName, fileInfo.Length);

        // Read the text file
        StreamReader r = fileInfo.OpenText();
        string textLine;
        while ((textLine = r.ReadLine()) != null) {
            Console.WriteLine(textLine);
        }
        r.Close();

    

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Summary

Creates a write-only FileStream.

C# Syntax:

public FileStream OpenWrite();

Return Value:

A new write-only unshared FileStream object.

Exceptions

Exception Type	Condition
UnauthorizedAccessException	path is read-only or a directory.
DirectoryNotFoundException	The directory is not found.

        // Create a temporary file.
        string      fileName = Path.GetTempFileName();
        FileInfo    fileInfo = new FileInfo(fileName);

        // Write the current time to the file in binary form.
        DateTime   currentTime = DateTime.Now;
        FileStream fileWriteStream = fileInfo.OpenWrite();
        BinaryFormatter binaryFormatter = new BinaryFormatter();
        binaryFormatter.Serialize(fileWriteStream, currentTime);
        fileWriteStream.Close();

        // Read the time back from the file.
        FileStream fileReadStream = fileInfo.OpenRead();
        DateTime   timeRead = (DateTime)binaryFormatter.Deserialize(fileReadStream);
        fileReadStream.Close();

        Console.WriteLine("Value written {0}", currentTime);
        Console.WriteLine("Value read    {0}", timeRead);

    

FileIOPermission for reading and writing files. Associated enumerations: FileIOPermissionAccess.Read, FileIOPermissionAccess.Write

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Inherited
See base class member description: System.IO.FileSystemInfo.Refresh

Summary

Refreshes the state of the object.

C# Syntax:

public void Refresh();

Exceptions

Exception Type	Condition
ArgumentException	The file is not found.
IOException	A device such as a disk drive is not ready.

FileSystemInfo.Refresh takes a snapshot of the file from the current file system.Refresh cannot correct the underlying file system even if the file system returns incorrect or outdated information. This can happen on platforms such as Windows 98.

Calls must be made to Refresh before attempting to get the attribute information, or the information will be outdated.

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Summary

Returns the fully qualified path as a string.

C# Syntax:

public override string ToString();

Return Value:

A string representing the fully qualified path.

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