复制大量文件的最快方法

Question

What is the fastest way to copy a lot of files?

I wrote a program using this to copy files:

string datapath;
string savepath;

// Something like this to set the destination for datapath, and savepath:
using (System.Windows.Forms.FolderBrowserDialog folderBrowserDialog = new System.Windows.Forms.FolderBrowserDialog())
{
    if (folderBrowserDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
    {
        datapath = folderBrowserDialog.SelectedPath;
    }
}

// And then to copy the files:
IEnumerable<string> files = Directory.EnumerateFiles(datapath, "*", SearchOption.AllDirectories);

foreach (var file in files)
{
    File.Copy(file, savepath, true);
}

I copied about 3600 files (16,5 GB total) with this method and it took me 11m 30sec. When i copy the same files with WinExplorer, it takes about 9 minutes, using the same Directories and doing nothing else with the hdd in both tests.

What are faster ways to handle this?

Answer 1

// A simple source for demonstration purposes. Modify this path as necessary.
string[] files = Directory.GetFiles(@"C:\Users\Public\Pictures\Sample Pictures", "*.jpg");
string newDir = @"C:\Users\Public\Pictures\Sample Pictures\Modified";
Directory.CreateDirectory(newDir);

// Method signature: Parallel.ForEach(IEnumerable<TSource> source, Action<TSource> body)
Parallel.ForEach(files, (currentFile) => 
    {
        // The more computational work you do here, the greater 
        // the speedup compared to a sequential foreach loop.
        string filename = Path.GetFileName(currentFile);
        var bitmap = new Bitmap(currentFile);

        bitmap.RotateFlip(RotateFlipType.Rotate180FlipNone);
        bitmap.Save(Path.Combine(newDir, filename));

        // Peek behind the scenes to see how work is parallelized.
        // But be aware: Thread contention for the Console slows down parallel loops!!!

        Console.WriteLine($"Processing {filename} on thread {Thread.CurrentThread.ManagedThreadId}");
        //close lambda expression and method invocation
    });

Paralel Foreach may help you. Source : https://docs.microsoft.com/en-us/dotnet/standard/parallel-programming/how-to-write-a-simple-parallel-foreach-loop

Answer 2

You can take a look at this library: https://quickio.net/

The aim of this library is to provide the fastes way to copy files and retrieve file and folder structures by using win32 api calls.