for

var exts = new[] { "mp3", "jpg" };

你可以:

public IEnumerable<string> FilterFiles(string path, params string[] exts) {
    return
        Directory
        .EnumerateFiles(path, "*.*")
        .Where(file => exts.Any(x => file.EndsWith(x, StringComparison.OrdinalIgnoreCase)));
}

不要忘记新的。net 4目录。EnumerateFiles用于性能提升(目录和文件的区别是什么?EnumerateFiles vs Directory.GetFiles?) “IgnoreCase”应该比“ToLower”(。EndsWith("aspx"， stringcompare . ordinalignorecase)而不是。tolower ().EndsWith("aspx"))

但EnumerateFiles的真正好处体现在你拆分过滤器并合并结果时:

public IEnumerable<string> FilterFiles(string path, params string[] exts) {
    return 
        exts.Select(x => "*." + x) // turn into globs
        .SelectMany(x => 
            Directory.EnumerateFiles(path, x)
            );
}

如果你不需要将它们转换为glob(即exts = new[] {"*.mp3"， "*.jpg"})，它会变得更快一些。

基于以下LinqPad测试的性能评估(注意:Perf只是重复委托10000次) https://gist.github.com/zaus/7454021

(从'duplicate'重新发布和扩展，因为这个问题特别要求没有LINQ:多个文件扩展searchPattern for System.IO.Directory.GetFiles)

另一种使用Linq的方式，但是不需要返回所有内容并在内存中过滤。

var files = Directory.GetFiles("C:\\path", "*.mp3", SearchOption.AllDirectories).Union(Directory.GetFiles("C:\\path", "*.jpg", SearchOption.AllDirectories));

它实际上是对GetFiles()的2次调用，但我认为这与问题的精神是一致的，并以一个可枚举的形式返回它们。

下面是一种获得过滤文件的简单而优雅的方法

var allowedFileExtensions = ".csv,.txt";


var files = Directory.EnumerateFiles(@"C:\MyFolder", "*.*", SearchOption.TopDirectoryOnly)
                .Where(s => allowedFileExtensions.IndexOf(Path.GetExtension(s)) > -1).ToArray(); 

DirectoryInfo directory = new DirectoryInfo(Server.MapPath("~/Contents/"));

//Using Union

FileInfo[] files = directory.GetFiles("*.xlsx")
                            .Union(directory
                            .GetFiles("*.csv"))
                            .ToArray();

还有一个下降解决方案，似乎没有任何内存或性能开销，而且相当优雅:

string[] filters = new[]{"*.jpg", "*.png", "*.gif"};
string[] filePaths = filters.SelectMany(f => Directory.GetFiles(basePath, f)).ToArray();

下面的函数搜索多个以逗号分隔的模式。你也可以指定一个排除，例如:"!web。Config”将搜索所有文件并排除“web.config”。模式可以混合使用。

private string[] FindFiles(string directory, string filters, SearchOption searchOption)
{
    if (!Directory.Exists(directory)) return new string[] { };

    var include = (from filter in filters.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries) where !string.IsNullOrEmpty(filter.Trim()) select filter.Trim());
    var exclude = (from filter in include where filter.Contains(@"!") select filter);

    include = include.Except(exclude);

    if (include.Count() == 0) include = new string[] { "*" };

    var rxfilters = from filter in exclude select string.Format("^{0}$", filter.Replace("!", "").Replace(".", @"\.").Replace("*", ".*").Replace("?", "."));
    Regex regex = new Regex(string.Join("|", rxfilters.ToArray()));

    List<Thread> workers = new List<Thread>();
    List<string> files = new List<string>();

    foreach (string filter in include)
    {
        Thread worker = new Thread(
            new ThreadStart(
                delegate
                {
                    string[] allfiles = Directory.GetFiles(directory, filter, searchOption);
                    if (exclude.Count() > 0)
                    {
                        lock (files)
                            files.AddRange(allfiles.Where(p => !regex.Match(p).Success));
                    }
                    else
                    {
                        lock (files)
                            files.AddRange(allfiles);
                    }
                }
            ));

        workers.Add(worker);

        worker.Start();
    }

    foreach (Thread worker in workers)
    {
        worker.Join();
    }

    return files.ToArray();

}

用法:

foreach (string file in FindFiles(@"D:\628.2.11", @"!*.config, !*.js", SearchOption.AllDirectories))
            {
                Console.WriteLine(file);
            }