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");

只是找到了另一种方法。仍然不是一次操作，而是把它扔出去，看看其他人是怎么想的。

private void getFiles(string path)
{
    foreach (string s in Array.FindAll(Directory.GetFiles(path, "*", SearchOption.AllDirectories), predicate_FileMatch))
    {
        Debug.Print(s);
    }
}

private bool predicate_FileMatch(string fileName)
{
    if (fileName.EndsWith(".mp3"))
        return true;
    if (fileName.EndsWith(".jpg"))
        return true;
    return false;
}

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");

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

Using GetFiles search pattern for filtering the extension is not safe!! For instance you have two file Test1.xls and Test2.xlsx and you want to filter out xls file using search pattern *.xls, but GetFiles return both Test1.xls and Test2.xlsx I was not aware of this and got error in production environment when some temporary files suddenly was handled as right files. Search pattern was *.txt and temp files was named *.txt20181028_100753898 So search pattern can not be trusted, you have to add extra check on filenames as well.

我不知道哪种解决方案更好，但我用这个:

String[] ext = "*.ext1|*.ext2".Split('|');

            List<String> files = new List<String>();
            foreach (String tmp in ext)
            {
                files.AddRange(Directory.GetFiles(dir, tmp, SearchOption.AllDirectories));
            }