FileSystemInfo Class and FileSystemWatcher Class

Aug 26, 2008
by David Cumps

Part of my 2008 study notes for exam 70-536 (.NET Framework 2.0).

Overview

FileSystemInfo
- FileSystemInfo forms the base for FileInfo and DirectoryInfo, but not DriveInfo.
- Information contained by FileSystemInfo is cached on first call; use Refresh() to update it.
- Absolute, relative and UNC paths are allowed.
- Get information from Attributes using bitwise operators.
FileSystemWatcher
- Can be used to monitor a directory for creation, deletion, renaming and modification of files.
  - See NotifyFilters for possible watches.
- Filters can be set for both the file mask to watch (Filter) and the type of notifications (NotifyFilter).
- The internal buffer can overflow if too many notifications happen at once.
  - This will trigger the Error event, so you can deal with it.

Examples

Checking FileType

FileSystemInfo a = new FileInfo(@"\\davidcxp\Public\Hello.txt");
FileSystemInfo b = new DirectoryInfo(@"C:\Public");
 
Console.WriteLine("{0}: {1}, created at {2}", 
                    ((a.Attributes & FileAttributes.Directory) != 0) ? "Directory" : "File",
                    a.FullName,
                    a.CreationTime);
 
Console.WriteLine("{0}: {1}, created at {2}",
                    ((b.Attributes & FileAttributes.Directory) != 0) ? "Directory" : "File",
                    b.FullName,
                    b.CreationTime);

Watching Directory

static void Main(string[] args)
{
    FileSystemWatcher a = new FileSystemWatcher();
    a.Path = @"C:\Public\";
    a.Filter = "*.txt";
    a.NotifyFilter = NotifyFilters.FileName;
    a.Created += new FileSystemEventHandler(Change);
    a.Deleted += new FileSystemEventHandler(Change);
    a.Changed += new FileSystemEventHandler(Change);
    a.Renamed += new RenamedEventHandler(Renamed);
    a.EnableRaisingEvents = true;
 
    Console.ReadLine();
    // Created C:\Public\New Text Document.txt
    // Renamed C:\Public\New Text Document.txt C:\Public\Watch.txt
    // Deleted C:\Public\Watch.txt
}
 
static void Change(object sender, FileSystemEventArgs e)
{
    Console.WriteLine(e.ChangeType + " " + e.FullPath);
}
 
static void Renamed(object sender, RenamedEventArgs e)
{
    Console.WriteLine(e.ChangeType + " " + e.OldFullPath + " " + e.FullPath);
}