Reference a Set of File Paths Using a Regular Expression

Question

Can I do one read to disk with a regular expression instead of doing this three times?

var path = HttpContext.Current.Server.MapPath(string.Format("~/Assets/Images/{0}.png", id)); 

if (!File.Exists(path))
{
    path = HttpContext.Current.Server.MapPath(string.Format("~/Assets/Images/{0}.jpg", id));

    if (!File.Exists(path))
    {
        path = HttpContext.Current.Server.MapPath(string.Format("~/Assets/Images/{0}.gif", id));

Answer 1

Assuming you don't care which you hit:

using System.IO

string imagesPath = HttpContext.Current.Server.MapPath("~/Assets/Images");
string path = null;
foreach (var filePath in Directory.GetFiles(imagesPath, id + ".*"))
{
    switch (Path.GetExtension(filePath))
    {
       case ".png":
       case ".jpg":
       case ".gif":
           path = filePath;
           break;
    }
}

If path is not null you found one.

Answer 2

Try something like this (only works in .NET4 and after):

string folder = HttpContext.Current.Server.MapPath("~/Assets/Images/");
string[] extensions = { ".jpg", ".gif", ".png" };
bool exists = Directory.EnumerateFiles(folder, "*.*", SearchOption.TopDirectoryOnly)
                 .Any(f => extensions.Contains(Path.GetExtension(f)));