Just to add to what DaveKerr said: SQL server always wants dates in ISO format: yyyy-MM-dd, so the solution he gave may help, but probably will need changes, as the ToShortDateString method returns the date in the format appropriate to your current locale.
Instead, consider using
date.ToString("yyyy-MM-dd")
Or, (preferably) using it as a SQL Parameter instead - this would mean changing your
display_outliad_f
method quite a bit, but is a very good idea in the long run.
All of this may still not do what you want - it assumes that you are storing
date_outlaid
as a DateTime in your SQL database.