Sorting Files by date

Question

I am using such code to compare files to sort by date..

FileInfo f = new FileInfo(name1);
FileInfo f1 = new FileInfo(name2);
if (f.Exists && f1.Exists)
   output = DateTime.Compare(f.LastWriteTime, f1.LastWriteTime);

Is there any better and faster way to sort by Date?

At a time i can compare only 2 items...

I could not sort by getting all files from directory.

Answer 1

You can use LINQ:

var sortedFiles = new DirectoryInfo(@"D:\samples").GetFiles()
                                                  .OrderBy(f => f.LastWriteTime)
                                                  .ToList();

Answer 2

    DirectoryInfo directoryInfo = new DirectoryInfo(@"D:\Temp");
    var result = directoryInfo.GetFiles("*.*",SearchOption.AllDirectories).OrderBy(t => t.LastWriteTime).ToList();

Answer 3

What about using Array.Sort ?

string[] fileNames = Directory.GetFiles("directory ", "*.*");
DateTime[] creationTimes = new DateTime[fileNames.Length];
for (int i = 0; i < fileNames.Length; i++)
    creationTimes[i] = new FileInfo(fileNames[i]).CreationTime;
Array.Sort(creationTimes, fileNames);

Answer 4

This is another way of doing it for the whole directory:dateCompareFileInfo

if (Directory.Exists(DIRECTORY_NAME))
{
     DirectoryInfo di = new DirectoryInfo(DIRECTORY_NAME);
     FileInfo[] logFiles = di.GetFiles("AN-10-log.txt*");

     DateCompareFileInfo dateCompareFileInfo = new DateCompareFileInfo();

     Array.Sort(logFiles, dateCompareFileInfo);
}

And the you need a new DateCompareFileInfo class that implements IComparer:

class DateCompareFileInfo : IComparer<FileInfo>
{
    /// <summary>
    /// Compare the last dates of the File infos
    /// </summary>
    /// <param name="fi1">First FileInfo to check</param>
    /// <param name="fi2">Second FileInfo to check</param>
    /// <returns></returns>
    public int Compare(FileInfo fi1, FileInfo fi2)
    {
        int result;
        if (fi1.LastWriteTime == fi2.LastWriteTime)
        {
            result = 0;
        }
        else if (fi1.LastWriteTime < fi2.LastWriteTime)
        {
            result = 1;
        }
        else
        {
            result = -1;
        }

        return result;
    }
}

Answer 5

IMPORTANT - When ordering by LastWriteTime, it should be noted that if the file has never been modified, this date may return 1601 or 1600. Here is what MSDN says:

If the file described in the path parameter does not exist, this method returns 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC), adjusted to local time.

If your timezone is PST, like me the date will actually be 12/31/1600. To get around this and write more robust code you might consider something like this:

.OrderByDescending(f => f.LastWriteTime.Year <= 1601 ? f.CreationTime : f.LastWriteTime)