Hi
Try this
Html
<asp:FileUpload ID="fuResumeFile" runat="server" />
<asp:Button runat="server" Text="Upload" OnClick="Upload" />
C# Code
string fileName = Path.GetFileNameWithoutExtension(Path.GetRandomFileName()) + DateTime.Now.ToString("dd_MM_yyyy_hh_mm_ss") + Path.GetExtension(this.fuResumeFile.FileName);
string filePath = Server.MapPath("~/Resumes/") + fileName;
this.fuResumeFile.SaveAs(filePath);