How to delete files programmatically?

Question

Here is the code that I use to close my application, its associated processes and to delete all the files that have been extracted during the use of the application:

private void Quit_Click(object sender, RoutedEventArgs e) //close the application
{
    //kill cinector after all import is done
    Process[] processes = Process.GetProcesses();
    for (int i = 0; i < processes.Count(); i++)
    {
        if (processes[i].ProcessName.ToLower().Contains("CinectorProcess"))
        {
            processes[i].Kill();
        }
    }

    //also kill powerpoint just in case

    for (int i = 0; i < processes.Count(); i++)
    {
        if (processes[i].ProcessName.ToLower().Contains("powerpnt"))
        {
            processes[i].Kill();
        }
    }

    //kill the engine
    ShutdownEngine();

    //kill the main app
    App.Current.Shutdown();

    //also delete all three folders

    //slides_png_prev
    if (Directory.Exists(slides_png_prev))
    {
        Thumbnails = null;
        Directory.Delete(slides_png_prev, true);
    }

    //slides_png
    if (Directory.Exists(slides_png))
    {
        Directory.Delete(slides_png, true);
    }

    //slides_png_prev_seleect
    if (Directory.Exists(slides_png_prev_seleect))
    {
        Directory.Delete(slides_png_prev_seleect, true);
    }
}

However, the problem is that when it tries to delete the files (which are the images used somewhere in the app) it shows the following exception:

"The process cannot access the file because it is being used by another process."

Update: I found that the process 'Mastersolution.vhost.exe' is holding all the files that I am attempting to delete. Mastersolution is actually the main app that I am closing on the line App.Current.Shutdown(); So I need to somehow disconnect the files from the main application prior to deleting them. But hoe to do this?

Answer 1

Store your files in a temp directory and let the operating system handle it.

See Path.GetTempPath and Path.GetTempFileName.

Answer 2

First you should determine, which file in the folder is locked - instead of deleting whole folder, delete individual files. Then check with Process Explorer and Ctrl+F what process really uses the undeletable file.

Also you can use the method WhoIsLocking in this code.

https://bitbucket.org/snippets/wiip/nnGX

You can use it to determine, which process locks the file. Then you can write something like this to kill this process automatically:

         List<Process> lp = FileUtil.WhoIsLocking(fileName);
         foreach (Process p in lp)
         {
                 p.Kill();
         }

This is last workaround when there are no better options, like closing the file in your app, closing Powerpoint using automation etc.