Question

Any suggestions on how to improve this method? I am currently using it to select a single wallpaper from a directory of wallpapers

I know your not supposed to use arraylist anymore but i couldnt think of a altrnative also im not sure how to filter for more than just one type of file (ie jpg gif png) in the directory info.

any suggestions or tweaks would be fantastic

private string getrandomfile(string path)         {             ArrayList al = new ArrayList();             DirectoryInfo di = new DirectoryInfo(path);             FileInfo[] rgFiles = di.GetFiles('*.*');             foreach (FileInfo fi in rgFiles)             {                 al.Add(fi.FullName);             }              Random r = new Random();             int x = r.Next(0,al.Count);              return al[x].ToString();          } 

Thanks

Crash

Answer 1

Changed to use a single instance of the pseudo-random number generator.

// Use a class variable so that the RNG is only created once. private Random generator; private Random Generator {     get     {         if (this.generator == null)         {            this.generator = new Random();         }         return this.generator;     } } private string getrandomfile(string path) {     string file = null;     if (!string.IsNullOrEmpty(path))     {         var extensions = new string[] { '.png', '.jpg', '.gif' };         try         {             var di = new DirectoryInfo(path);             var rgFiles = di.GetFiles('*.*')                             .Where( f => extensions.Contains( f.Extension                                                                .ToLower() );             int fileCount = rgFiles.Count();             if (fileCount > 0)             {                 int x = this.Generator.Next( 0, fileCount );                 file = rgFiles.ElementAt(x).FullName;             }         }         // probably should only catch specific exceptions         // throwable by the above methods.         catch {}     }     return file; }