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。

没有。试试下面的方法:

List<string> _searchPatternList = new List<string>();
    ...
    List<string> fileList = new List<string>();
    foreach ( string ext in _searchPatternList )
    {
        foreach ( string subFile in Directory.GetFiles( folderName, ext  )
        {
            fileList.Add( subFile );
        }
    }

    // Sort alpabetically
    fileList.Sort();

    // Add files to the file browser control    
    foreach ( string fileName in fileList )
    {
        ...;
    }

摘自:http://blogs.msdn.com/markda/archive/2006/04/20/580075.aspx

List<string> FileList = new List<string>();
DirectoryInfo di = new DirectoryInfo("C:\\DirName");

IEnumerable<FileInfo> fileList = di.GetFiles("*.*");

//Create the query
IEnumerable<FileInfo> fileQuery = from file in fileList
                                  where (file.Extension.ToLower() == ".jpg" || file.Extension.ToLower() == ".png")
                                  orderby file.LastWriteTime
                                  select file;

foreach (System.IO.FileInfo fi in fileQuery)
{
    fi.Attributes = FileAttributes.Normal;
    FileList.Add(fi.FullName);
}

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

//Using Union

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

我知道这是一个老问题，但LINQ:(.NET40+)

var files = Directory.GetFiles("path_to_files").Where(file => Regex.IsMatch(file, @"^.+\.(wav|mp3|txt)$"));

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();