Csharp/C Sharp/File Stream/File
Содержание
- 1 Delete a file
- 2 File class to check whether a file exists, open and read
- 3 Get File Access Control
- 4 Get file Creation Time
- 5 illustrates the FileAttributes enumeration
- 6 illustrates the FileInfo class
- 7 illustrates the FileSystemWatcher class
- 8 Uses methods in the File class to check the status of a file
- 9 Uses methods in the File class to check whether a file exists
Delete a file
<source lang="csharp"> using System; using System.IO; class MainClass {
static void Main() {
string tempFile = Path.GetTempFileName();
Console.WriteLine("Using " + tempFile);
using (FileStream fs = new FileStream(tempFile, FileMode.Open)) {
// (Write some data.)
}
// Now delete the file.
File.Delete(tempFile);
}
}
</source>
File class to check whether a file exists, open and read
<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794
- /
// cp.cs -- Uses methods in the File class to check whether a file exists. // If it exists, it then opens and reads the file to the console. // // Compile this program with the following command line // C:>csc cp.cs using System; using System.IO; namespace nsStreams {
public class cp
{
static public void Main (string [] args)
{
if (args.Length < 2)
{
Console.WriteLine ("usage: cp <copy from> <copy to>");
return;
}
if (!File.Exists (args[0]))
{
Console.WriteLine (args[0] + " does not exist");
return;
}
bool bOverwrite = false;
if (File.Exists (args[1]))
{
Console.Write (args[1] + " already exists. Overwrite [Y/N]? ");
string reply = Console.ReadLine ();
char ch = (char) (reply[0] & (char) 0xdf);
if (ch != "Y")
return;
bOverwrite = true;
}
File.Copy (args[0], args[1], bOverwrite);
}
}
}
</source>
Get File Access Control
<source lang="csharp">
using System; using System.IO; using System.Security.AccessControl; class MainClass {
static void Main(string[] args) {
FileStream stream;
string fileName;
fileName = Path.GetRandomFileName();
using (stream = new FileStream(fileName, FileMode.Create)) {
// Do something.
}
SetRule(fileName, "Everyone", FileSystemRights.Read, AccessControlType.Deny);
try {
stream = new FileStream(fileName, FileMode.Create);
} catch (Exception ex) {
Console.WriteLine(ex.ToString());
} finally {
stream.Close();
stream.Dispose();
}
}
static void AddRule(string filePath, string account, FileSystemRights rights, AccessControlType controlType) {
FileSecurity fSecurity = File.GetAccessControl(filePath);
fSecurity.AddAccessRule(new FileSystemAccessRule(account, rights, controlType));
File.SetAccessControl(filePath, fSecurity);
}
static void SetRule(string filePath, string account, FileSystemRights rights, AccessControlType controlType) {
FileSecurity fSecurity = File.GetAccessControl(filePath);
fSecurity.ResetAccessRule(new FileSystemAccessRule(account, rights, controlType));
File.SetAccessControl(filePath, fSecurity);
}
}
</source>
Get file Creation Time
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/* Example15_3.cs illustrates the File class
- /
using System; using System.Windows.Forms; using System.IO; public class Example15_3 {
[STAThread]
public static void Main()
{
// create and show an open file dialog
OpenFileDialog dlgOpen = new OpenFileDialog();
if (dlgOpen.ShowDialog() == DialogResult.OK)
{
// use the File class to return info about the file
string s = dlgOpen.FileName;
Console.WriteLine("Filename " + s);
Console.WriteLine(" Created at " + File.GetCreationTime(s));
Console.WriteLine(" Accessed at " +
File.GetLastAccessTime(s));
}
}
}
</source>
illustrates the FileAttributes enumeration
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/* Example15_4.cs illustrates the FileAttributes enumeration
- /
using System; using System.Windows.Forms; using System.IO; public class Example15_4 {
// the DecipherAttributes method turns file attributes
// into something easier for people to read
public static void DecipherAttributes(FileAttributes f)
{
if ((f & FileAttributes.Archive) == FileAttributes.Archive)
Console.WriteLine("Archive");
if ((f & FileAttributes.rupressed) == FileAttributes.rupressed)
Console.WriteLine("Compressed");
if ((f & FileAttributes.Device) == FileAttributes.Device)
Console.WriteLine("Device");
if ((f & FileAttributes.Directory) == FileAttributes.Directory)
Console.WriteLine("Directory");
if ((f & FileAttributes.Encrypted) == FileAttributes.Encrypted)
Console.WriteLine("Encrypted");
if ((f & FileAttributes.Hidden) == FileAttributes.Hidden)
Console.WriteLine("Hidden");
if ((f & FileAttributes.NotContentIndexed) == FileAttributes.NotContentIndexed)
Console.WriteLine("NotContentIndexed");
if ((f & FileAttributes.Offline) == FileAttributes.Offline)
Console.WriteLine("Offline");
if ((f & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
Console.WriteLine("ReadOnly");
if ((f & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint)
Console.WriteLine("ReparsePoint");
if ((f & FileAttributes.SparseFile) == FileAttributes.SparseFile)
Console.WriteLine("SparseFile");
if ((f & FileAttributes.System) == FileAttributes.System)
Console.WriteLine("System");
if ((f & FileAttributes.Temporary) == FileAttributes.Temporary)
Console.WriteLine("Temporary");
}
[STAThread]
public static void Main()
{
// create and show an open file dialog
OpenFileDialog dlgOpen = new OpenFileDialog();
if (dlgOpen.ShowDialog() == DialogResult.OK)
{
// retrieve and show the file attributes
FileAttributes f = File.GetAttributes(dlgOpen.FileName);
Console.WriteLine("Filename " + dlgOpen.FileName +
" has attributes:");
DecipherAttributes(f);
}
}
}
</source>
illustrates the FileInfo class
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/* Example15_5.cs illustrates the FileInfo class
- /
using System; using System.Windows.Forms; using System.IO; public class Example15_5 {
[STAThread]
public static void Main()
{
// create and show an open file dialog
OpenFileDialog dlgOpen = new OpenFileDialog();
if (dlgOpen.ShowDialog() == DialogResult.OK)
{
// use the File class to return info about the file
FileInfo fi = new FileInfo(dlgOpen.FileName);
Console.WriteLine("Filename " + fi.FullName );
Console.WriteLine(" Created at " + fi.CreationTime );
Console.WriteLine(" Accessed at " + fi.LastAccessTime );
}
}
}
</source>
illustrates the FileSystemWatcher class
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/* Example15_9.cs illustrates the FileSystemWatcher class
- /
using System; using System.IO; public class Example15_9 {
// event handler for file change
public static void OnChanged(object source, FileSystemEventArgs e)
{
// dump info to the screen
Console.WriteLine("Change to " + e.FullPath + ": " +
e.ChangeType);
}
public static void Main()
{
// create a watcher for the c: drive
FileSystemWatcher fsw = new FileSystemWatcher("c:\\");
fsw.IncludeSubdirectories = true;
// hook up the event handler
fsw.Changed += new FileSystemEventHandler(OnChanged);
// turn on file watching
fsw.EnableRaisingEvents = true;
// And wait for the user to quit
Console.WriteLine("Press any key to exit");
int i = Console.Read();
}
}
</source>
Uses methods in the File class to check the status of a file
<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794
- /
// Status.cs -- Uses methods in the File class to check the status of a file. // // Compile this program with the following command line // C:>csc Status.cs using System; using System.IO; namespace nsStreams {
public class Status
{
static public void Main (string [] args)
{
if (args.Length == 0)
{
Console.WriteLine ("Please enter a file name");
return;
}
if (!File.Exists (args[0]))
{
Console.WriteLine (args[0] + " does not exist");
return;
}
DateTime created = File.GetCreationTime (args[0]);
DateTime accessed = File.GetLastAccessTime (args[0]);
DateTime written = File.GetLastWriteTime (args[0]);
Console.WriteLine ("File " + args[0] + ":");
string str = created.ToString();
int index = str.IndexOf (" ");
Console.WriteLine ("\tCreated on " + str.Substring (0, index) + " at " + str.Substring (index + 1));
str = accessed.ToString();
index = str.IndexOf (" ");
Console.WriteLine ("\tLast accessed on " + str.Substring (0, index) + " at " + str.Substring (index + 1));
str = written.ToString();
index = str.IndexOf (" ");
Console.WriteLine ("\tLast written on " + str.Substring (0, index) + " at " + str.Substring (index + 1));
}
}
}
</source>
Uses methods in the File class to check whether a file exists
<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794
- /
// Exists.cs -- Uses methods in the File class to dheck whether a file exists. // If it exists, it then opens and reads the file to the console. // // Compile this program with the following command line // C:>csc Exists.cs using System; using System.IO; namespace nsStreams {
public class Exists
{
static public void Main (string [] args)
{
if (args.Length == 0)
{
Console.WriteLine ("Please enter a file name");
return;
}
if (!File.Exists (args[0]))
{
Console.WriteLine (args[0] + " does not exist");
return;
}
StreamReader reader;
try
{
reader = File.OpenText (args[0]);
}
catch (Exception e)
{
Console.WriteLine (e.Message);
Console.WriteLine ("Cannot open " + args[0]);
return;
}
while (reader.Peek() >= 0)
{
Console.WriteLine (reader.ReadLine ());
}
reader.Close ();
}
}
}
</source>
