Upload multiple files using single FileUpload control using C# and VB.Net in ASP.Net

How to upload multiple images with single fileupload control using asp.net with C#. and i'm not getting PostedFiles and HasFiles while i'm using AllowMultiple="true" into a control.

string filename = Path.GetFileName(FileUpload1.PostedFile.FileName);
FileUpload1.SaveAs(Server.MapPath("~/FilePath/" + filename));

Please let me know how can I do this? i'm a little bit confused.