This code was added to a custom form in SharePoint Designer. The code is in the XSL stylesheet and this was created to filter a Status Choice field based on its current status. The SelectCommand was used to do the filtering and it is just encoded CAML. This query checks the current status against a separate list that contains the "allowed" status values for the current status. This is used to drive an item through a certain process. A user can select a status but the choices are limited depending on where the item is in the process. The list also has a display text so the dropdown has a more descriptive text of what the user is selecting. The DVDropDownList then updates the actual status field which is a choice field in this case.