public string GetFileName(string controlId)
{
if(String.IsNullOrEmpty(controlId))
throw new ArgumentException("controlId cannot be empty", "controlId");
var currentContext = GetCurrentContext();
if(currentContext == null)
return String.Empty;
var postedFile = currentContext.Session[GetFullID(controlId)] as HttpPostedFile;
if(postedFile == null)
return String.Empty;
return postedFile.FileName;
}