دوست عزیز اینو بنویس

string location = HttpContext.Current.Server.MapPath("~/uploads/");
public string Save(HttpPostedFileBase file)
{
if (file==null)
{
return string.Empty;
}
if (!Directory.Exists(location))
{
Directory.CreateDirectory(location);
}
var virtualPath = Server.MapPath("~/uploads/" + file.FileName);

file.SaveAs(virtualPath);
return virtualPath;
}