有条件删除文件的更好方法是什么 [英] What is better way to delete file with condition

问题描述

我想在c#上构建一个win服务(没有UI)，它要做的就是:在目录列表上运行并删除X kb以上的文件. 我想要更好的性能，

I want to build a win service(no UI) on c# that all what it done is: run on list of directories and delete files that over then X kb. I want the better performance,

什么是更好的方法? 没有用于删除文件的纯异步功能，所以如果我想使用异步等待 我可以像这样包装此功能:

what is the better way to do this? there is no pure async function for delete file so if i want to use async await I can wrap this function like:

public static class FileExtensions {
   public static Task DeleteAsync(this FileInfo fi) {
      return Task.Factory.StartNew(() => fi.Delete() );
   }
}

并调用此函数，如:

FileInfo fi = new FileInfo(fileName);
await fi.DeleteAsync();

我认为跑步方式

foreach file on ListOfDirectories
{

  if(file.Length>1000)
      await file.DeleteAsync

}

，但是在此选项上，文件将一一删除(并且每个DeleteAsync将在threadPool中的线程上使用). 所以我不能从异步中赚钱，我可以1比1做到这一点.

but on this option the files will delete 1 by 1 (and every DeleteAsync will use on thread from the threadPool). so i not earn from the async, i can do it 1 by 1.

也许我想收集列表中的X个文件，然后将它们删除为AsParallel

maybe i think to collect X files on list and then delete them AsParallel

请帮助我找到更好的方法

please help me to find the better way

推荐答案

这可能会对您有所帮助.

this is may be can help you.

public static class FileExtensions
{
    public static Task<int> DeleteAsync(this IEnumerable<FileInfo> files)
    {
        var count = files.Count();
        Parallel.ForEach(files, (f) =>
        {
            f.Delete();
        });
        return Task.FromResult(count);
    }
    public static async Task<int> DeleteAsync(this DirectoryInfo directory, Func<FileInfo, bool> predicate)
    {
        return await directory.EnumerateFiles().Where(predicate).DeleteAsync();
    }
    public static async Task<int> DeleteAsync(this IEnumerable<FileInfo> files, Func<FileInfo, bool> predicate)
    {
        return await files.Where(predicate).DeleteAsync();
    }

}

        var _byte = 1;
        var _kb = _byte * 1000;
        var _mb = _kb * 1000;
        var _gb = _mb * 1000;
        DirectoryInfo d = new DirectoryInfo(@"C:\testDirectory");

        var deletedFileCount = await d.DeleteAsync(f => f.Length > _mb * 1);
        Debug.WriteLine("{0} Files larger than 1 megabyte deleted", deletedFileCount);
        // => 7 Files larger than 1 megabyte deleted

        deletedFileCount = await d.GetFiles("*.*",SearchOption.AllDirectories)
            .Where(f => f.Length > _kb * 10).DeleteAsync();

        Debug.WriteLine("{0} Files larger than 10 kilobytes deleted", deletedFileCount);
        // => 11 Files larger than 10 kilobytes deleted

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