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);
}

让你想要的扩展名为一个字符串，即“.mp3.jpg.wma.wmf”，然后检查每个文件是否包含你想要的扩展名。 这适用于。net 2.0，因为它不使用LINQ。

string myExtensions=".jpg.mp3";

string[] files=System.IO.Directory.GetFiles("C:\myfolder");

foreach(string file in files)
{
   if(myExtensions.ToLower().contains(System.IO.Path.GetExtension(s).ToLower()))
   {
      //this file has passed, do something with this file

   }
}

这种方法的优点是你可以添加或删除扩展，而不需要编辑代码，即添加png图像，只需写myExtensions=".jpg.mp3.png"。

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)$"));

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

或者你可以直接将扩展名字符串转换为string ^

vector <string>  extensions = { "*.mp4", "*.avi", "*.flv" };
for (int i = 0; i < extensions.size(); ++i)
{
     String^ ext = gcnew String(extensions[i].c_str());;
     String^ path = "C:\\Users\\Eric\\Videos";
     array<String^>^files = Directory::GetFiles(path,ext);
     Console::WriteLine(ext);
     cout << " " << (files->Length) << endl;
}

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
}