Combine two (or more) FileInfo's...

Question

I have something similar to this:

var d1 = new DirectoryInfo(Path.Combine(source, @"bills_save." + dt));
var d2 = new DirectoryInfo(Path.Combine(source, @"reports_save." + dt));

var f1 = d1.GetFiles();
var f2 = d2.GetFiles();

I want to get, and combine, all the filenames into one FileInfo list. Would make my parsing a lot easier. Concat, AddRange, join... nothing seems to work. Most of what I see is for adding 2 lists, arrays.

Answer 1

Well, Concat certainly should work:

// f3 will be IEnumerable<FileInfo>
var f3 = f1.Concat(f2);

If you need an array or a list, call ToArray or ToList appropriately:

var list3 = f1.Concat(f2).ToList();
var array3 = f1.Concat(f2).ToArray();

By the way, your verbatim string literal doesn't need to be verbatim - it doesn't contain anything which would need escaping.

Answer 2

You need to make a List<FileInfo>, like this:

List<FileInfo> files = new List<FileInfo>();
files.AddRange(d1.GetFiles());
files.AddRange(d2.GetFiles());

If you have a collection of DirectoryInfos, you can call SelectMany:

IEnumerable<FileInfo> files = directories.SelectMany(d => d.GetFiles());