具有多个扩展名的 GetFiles

I'm not sure if that is possible. The MSDN GetFiles reference says a search pattern, not a list of search patterns.

I might be inclined to fetch each list separately and "foreach" them into a final list.

You can't do that, because GetFiles only accepts a single search pattern. Instead, you can call GetFiles with no pattern, and filter the results in code:

string[] extensions = new[] { ".jpg", ".tiff", ".bmp" };


FileInfo[] files =
dinfo.GetFiles()
.Where(f => extensions.Contains(f.Extension.ToLower()))
.ToArray();

If you're working with .NET 4, you can use the EnumerateFiles method to avoid loading all FileInfo objects in memory at once:

string[] extensions = new[] { ".jpg", ".tiff", ".bmp" };


FileInfo[] files =
dinfo.EnumerateFiles()
.Where(f => extensions.Contains(f.Extension.ToLower()))
.ToArray();

The following retrieves the jpg, tiff and bmp files and gives you an IEnumerable<FileInfo> over which you can iterate:

var files = dinfo.GetFiles("*.jpg")
.Concat(dinfo.GetFiles("*.tiff"))
.Concat(dinfo.GetFiles("*.bmp"));

If you really need an array, simply stick .ToArray() at the end of this.

I know there is a more elegant way to do this and I'm open to suggestions... this is what I did:

          try
{




// Set directory for list to be made of
DirectoryInfo jpegInfo = new DirectoryInfo(destinationFolder);
DirectoryInfo jpgInfo = new DirectoryInfo(destinationFolder);
DirectoryInfo gifInfo = new DirectoryInfo(destinationFolder);
DirectoryInfo tiffInfo = new DirectoryInfo(destinationFolder);
DirectoryInfo bmpInfo = new DirectoryInfo(destinationFolder);


// Set file type
FileInfo[] Jpegs = jpegInfo.GetFiles("*.jpeg");
FileInfo[] Jpgs = jpegInfo.GetFiles("*.jpg");
FileInfo[] Gifs = gifInfo.GetFiles("*.gif");
FileInfo[] Tiffs = gifInfo.GetFiles("*.tiff");
FileInfo[] Bmps = gifInfo.GetFiles("*.bmp");


//  listBox1.Items.Add(@"");  // Hack for the first list item no preview problem
// Iterate through each file, displaying only the name inside the listbox...
foreach (FileInfo file in Jpegs)
{
listBox1.Items.Add(file.Name);
Photo curPhoto = new Photo();
curPhoto.PhotoLocation = file.FullName;
metaData.AddPhoto(curPhoto);
}


foreach (FileInfo file in Jpgs)
{
listBox1.Items.Add(file.Name);
Photo curPhoto = new Photo();
curPhoto.PhotoLocation = file.FullName;
metaData.AddPhoto(curPhoto);
}
foreach (FileInfo file in Gifs)
{
listBox1.Items.Add(file.Name);
Photo curPhoto = new Photo();
curPhoto.PhotoLocation = file.FullName;
metaData.AddPhoto(curPhoto);
}
foreach (FileInfo file in Tiffs)
{
listBox1.Items.Add(file.Name);
Photo curPhoto = new Photo();
curPhoto.PhotoLocation = file.FullName;
metaData.AddPhoto(curPhoto);
}
foreach (FileInfo file in Bmps)
{
listBox1.Items.Add(file.Name);
Photo curPhoto = new Photo();
curPhoto.PhotoLocation = file.FullName;
metaData.AddPhoto(curPhoto);
}

Why not create an extension method? That's more readable.

public static IEnumerable<FileInfo> GetFilesByExtensions(this DirectoryInfo dir, params string[] extensions)
{
if (extensions == null)
throw new ArgumentNullException("extensions");
IEnumerable<FileInfo> files = Enumerable.Empty<FileInfo>();
foreach(string ext in extensions)
{
files = files.Concat(dir.GetFiles(ext));
}
return files;
}

EDIT: a more efficient version:

public static IEnumerable<FileInfo> GetFilesByExtensions(this DirectoryInfo dir, params string[] extensions)
{
if (extensions == null)
throw new ArgumentNullException("extensions");
IEnumerable<FileInfo> files = dir.EnumerateFiles();
return files.Where(f => extensions.Contains(f.Extension));
}

Usage:

DirectoryInfo dInfo = new DirectoryInfo(@"c:\MyDir");
dInfo.GetFilesByExtensions(".jpg",".exe",".gif");

You can get every file, then filter the array:

public static IEnumerable<FileInfo> GetFilesByExtensions(this DirectoryInfo dirInfo, params string[] extensions)
{
var allowedExtensions = new HashSet<string>(extensions, StringComparer.OrdinalIgnoreCase);


return dirInfo.EnumerateFiles()
.Where(f => allowedExtensions.Contains(f.Extension));
}

This will be (marginally) faster than every other answer here.
In .Net 3.5, replace EnumerateFiles with GetFiles (which is slower).

And use it like this:

var files = new DirectoryInfo(...).GetFilesByExtensions(".jpg", ".mov", ".gif", ".mp4");

You can use LINQ Union method:

dir.GetFiles("*.txt").Union(dir.GetFiles("*.jpg")).ToArray();