我有同样的问题，找不到正确的解决方案，所以我写了一个函数叫GetFiles:

/// <summary>
/// Get all files with a specific extension
/// </summary>
/// <param name="extensionsToCompare">string list of all the extensions</param>
/// <param name="Location">string of the location</param>
/// <returns>array of all the files with the specific extensions</returns>
public string[] GetFiles(List<string> extensionsToCompare, string Location)
{
    List<string> files = new List<string>();
    foreach (string file in Directory.GetFiles(Location))
    {
        if (extensionsToCompare.Contains(file.Substring(file.IndexOf('.')+1).ToLower())) files.Add(file);
    }
    files.Sort();
    return files.ToArray();
}

这个函数只调用Directory.Getfiles()一次。

例如，像这样调用函数:

string[] images = GetFiles(new List<string>{"jpg", "png", "gif"}, "imageFolder");

编辑:要获得一个具有多个扩展名的文件，请使用这个文件:

/// <summary>
    /// Get the file with a specific name and extension
    /// </summary>
    /// <param name="filename">the name of the file to find</param>
    /// <param name="extensionsToCompare">string list of all the extensions</param>
    /// <param name="Location">string of the location</param>
    /// <returns>file with the requested filename</returns>
    public string GetFile( string filename, List<string> extensionsToCompare, string Location)
    {
        foreach (string file in Directory.GetFiles(Location))
        {
            if (extensionsToCompare.Contains(file.Substring(file.IndexOf('.') + 1).ToLower()) &&& file.Substring(Location.Length + 1, (file.IndexOf('.') - (Location.Length + 1))).ToLower() == filename) 
                return file;
        }
        return "";
    }

例如，像这样调用函数:

string image = GetFile("imagename", new List<string>{"jpg", "png", "gif"}, "imageFolder");

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(); 

在。net 2.0中(没有Linq):

public static List<string> GetFilez(string path, System.IO.SearchOption opt,  params string[] patterns)
{
    List<string> filez = new List<string>();
    foreach (string pattern in patterns)
    {
        filez.AddRange(
            System.IO.Directory.GetFiles(path, pattern, opt)
        );
    }


    // filez.Sort(); // Optional
    return filez; // Optional: .ToArray()
}

然后使用它:

foreach (string fn in GetFilez(path
                             , System.IO.SearchOption.AllDirectories
                             , "*.xml", "*.xml.rels", "*.rels"))
{}

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);
            }

如果你有一个很大的扩展列表要检查，你可以使用下面的。我不想创建很多OR语句，所以我修改了lette写的东西。

string supportedExtensions = "*.jpg,*.gif,*.png,*.bmp,*.jpe,*.jpeg,*.wmf,*.emf,*.xbm,*.ico,*.eps,*.tif,*.tiff,*.g01,*.g02,*.g03,*.g04,*.g05,*.g06,*.g07,*.g08";
foreach (string imageFile in Directory.GetFiles(_tempDirectory, "*.*", SearchOption.AllDirectories).Where(s => supportedExtensions.Contains(Path.GetExtension(s).ToLower())))
{
    //do work here
}

是什么

string[] filesPNG = Directory.GetFiles(path, "*.png");
string[] filesJPG = Directory.GetFiles(path, "*.jpg");
string[] filesJPEG = Directory.GetFiles(path, "*.jpeg");

int totalArraySizeAll = filesPNG.Length + filesJPG.Length + filesJPEG.Length;
List<string> filesAll = new List<string>(totalArraySizeAll);
filesAll.AddRange(filesPNG);
filesAll.AddRange(filesJPG);
filesAll.AddRange(filesJPEG);