InfoPath Dev

I am just getting back to this and need more clarification. Tried several things but missing something. InfoPath 2010 I have a date time field and a rooms list. Once a date and time is entered: -Populate a combo box with rooms not booked during that period Could you give me a little more information. Thanks

I have created a booking request form that submits the form to a SharePoint list and all of that works. What I need no to implement is when a user selects a time slot the next step is to query that SharePoint list and populate a list of available rooms for that open time slot. Example I pick November 14 10:00AM to 11:00AM then query the same ...

Any help would be appreciated So here is the error: System.NullReferenceException Object reference not set to an instance of an object. at repeating_table_to_list.FormCode.CTRL70_5_Clicked(Object sender, ClickedEventArgs e) at Microsoft.Office.InfoPath.Internal.ButtonEventHost.OnButtonClick(DocActionEvent pEvent) at ...