GetFiles is extremely slow.- If you are invoking it from a website, you might just throw a new Thread which does this trick.
- An ASP.NET AJAX call that returns whether there are still matching files, can be used to do basic progress updates.
Below an implementation of a fast Win32 wrapping for GetFiles, use it in combination with a new Thread and an AJAX function like: GetFilesUnmanaged(@"C:\myDir", "*.txt*).GetEnumerator().MoveNext().
Usage
Thread workerThread = new Thread(new ThreadStart((MethodInvoker)(()=>
{
foreach(var file in GetFilesUnmanaged(@"C:\myDir", "*.txt"))
File.Delete(file);
})));
workerThread.Start();
//just go on with your normal requests, the directory will be cleaned while the user can just surf around
public static IEnumerable<string> GetFilesUnmanaged(string directory, string filter)
{
return new FilesFinder(Path.Combine(directory, filter))
.Where(f => (f.Attributes & FileAttributes.Normal) == FileAttributes.Normal
|| (f.Attributes & FileAttributes.Archive) == FileAttributes.Archive)
.Select(s => s.FileName);
}
}
public class FilesEnumerator : IEnumerator<FoundFileData>
{
#region Interop imports
private const int ERROR_FILE_NOT_FOUND = 2;
private const int ERROR_NO_MORE_FILES = 18;
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr FindFirstFile(string lpFileName, out WIN32_FIND_DATA lpFindFileData);
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern bool FindNextFile(SafeHandle hFindFile, out WIN32_FIND_DATA lpFindFileData);
#endregion
#region Data Members
private readonly string _fileName;
private SafeHandle _findHandle;
private WIN32_FIND_DATA _win32FindData;
#endregion
public FilesEnumerator(string fileName)
{
_fileName = fileName;
_findHandle = null;
_win32FindData = new WIN32_FIND_DATA();
}
#region IEnumerator<FoundFileData> Members
public FoundFileData Current
{
get
{
if (_findHandle == null)
throw new InvalidOperationException("MoveNext() must be called first");
return new FoundFileData(ref _win32FindData);
}
}
object IEnumerator.Current
{
get { return Current; }
}
public bool MoveNext()
{
if (_findHandle == null)
{
_findHandle = new SafeFileHandle(FindFirstFile(_fileName, out _win32FindData), true);
if (_findHandle.IsInvalid)
{
int lastError = Marshal.GetLastWin32Error();
if (lastError == ERROR_FILE_NOT_FOUND)
return false;
throw new Win32Exception(lastError);
}
}
else
{
if (!FindNextFile(_findHandle, out _win32FindData))
{
int lastError = Marshal.GetLastWin32Error();
if (lastError == ERROR_NO_MORE_FILES)
return false;
throw new Win32Exception(lastError);
}
}
return true;
}
public void Reset()
{
if (_findHandle.IsInvalid)
return;
_findHandle.Close();
_findHandle.SetHandleAsInvalid();
}
public void Dispose()
{
_findHandle.Dispose();
}
#endregion
}
public class FilesFinder : IEnumerable<FoundFileData>
{
readonly string _fileName;
public FilesFinder(string fileName)
{
_fileName = fileName;
}
public IEnumerator<FoundFileData> GetEnumerator()
{
return new FilesEnumerator(_fileName);
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
public class FoundFileData
{
public string AlternateFileName;
public FileAttributes Attributes;
public DateTime CreationTime;
public string FileName;
public DateTime LastAccessTime;
public DateTime LastWriteTime;
public UInt64 Size;
internal FoundFileData(ref WIN32_FIND_DATA win32FindData)
{
Attributes = (FileAttributes)win32FindData.dwFileAttributes;
CreationTime = DateTime.FromFileTime((long)
(((UInt64)win32FindData.ftCreationTime.dwHighDateTime << 32) +
(UInt64)win32FindData.ftCreationTime.dwLowDateTime));
LastAccessTime = DateTime.FromFileTime((long)
(((UInt64)win32FindData.ftLastAccessTime.dwHighDateTime << 32) +
(UInt64)win32FindData.ftLastAccessTime.dwLowDateTime));
LastWriteTime = DateTime.FromFileTime((long)
(((UInt64)win32FindData.ftLastWriteTime.dwHighDateTime << 32) +
(UInt64)win32FindData.ftLastWriteTime.dwLowDateTime));
Size = ((UInt64)win32FindData.nFileSizeHigh << 32) + win32FindData.nFileSizeLow;
FileName = win32FindData.cFileName;
AlternateFileName = win32FindData.cAlternateFileName;
}
}
/// <summary>
/// Safely wraps handles that need to be closed via FindClose() WIN32 method (obtained by FindFirstFile())
/// </summary>
public class SafeFindFileHandle : SafeHandleZeroOrMinusOneIsInvalid
{
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool FindClose(SafeHandle hFindFile);
public SafeFindFileHandle(bool ownsHandle)
: base(ownsHandle)
{
}
protected override bool ReleaseHandle()
{
return FindClose(this);
}
}
// The CharSet must match the CharSet of the corresponding PInvoke signature
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct WIN32_FIND_DATA
{
public uint dwFileAttributes;
public FILETIME ftCreationTime;
public FILETIME ftLastAccessTime;
public FILETIME ftLastWriteTime;
public uint nFileSizeHigh;
public uint nFileSizeLow;
public uint dwReserved0;
public uint dwReserved1;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
public string cFileName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
public string cAlternateFileName;
}