Delete files from the folder older than 4 days

Question

I would like to run a timer for every 5 hours and delete the files from the folder older than 4 days. Could you please with sample code?

Answer 1

DateTime CutOffDate = DateTime.Now.AddDays(-4)
DirectoryInfo di = new DirectoryInfo(folderPath);
FileInfo[] fi = di.GetFiles();

for (int i = 0; i < fi.Length; i++)
{
    if (fi[i].LastWriteTime < CutOffDate)
    {
        File.Delete(fi[i].FullName);
    }
}

You can substitute LastWriteTime property for something else, that's just what I use when clearing out an Image Cache in an app I have.

EDIT:

Though this doesnt include the timer part... I'll let you figure that part out yourself. A little Googling should show you several ways to do it on a schedule.

Answer 2

Since it hasn't been mentioned, I would recommend using a System.Threading.Timer for something like this. Here's an example implementation:

System.Threading.Timer DeleteFileTimer = null;

private void CreateStartTimer()
{
    TimeSpan InitialInterval = new TimeSpan(0,0,5);
    TimeSpan RegularInterval = new TimeSpan(5,0,0);

    DeleteFileTimer = new System.Threading.Timer(QueryDeleteFiles, null, 
            InitialInterval, RegularInterval);

}

private void QueryDeleteFiles(object state)
{
    //Delete Files Here... (Fires Every Five Hours).
    //Warning: Don't update any UI elements from here without Invoke()ing
    System.Diagnostics.Debug.WriteLine("Deleting Files...");
}

private void StopDestroyTimer()
{
    DeleteFileTimer.Change(System.Threading.Timeout.Infinite,
    System.Threading.Timeout.Infinite);

    DeleteFileTimer.Dispose();
}

This way, you can run your file deletion code in a windows service with minimal hassle.