1. Form Design Aid Guide
  2. Loading Combo Box Fundamentals

Loading Combo Box Fundamentals

You can load a combo box control from any of these data sources:

  • Its associated DD UDCs.

  • Cache (using the Load from Cache system function).

  • Any source available to the Add Item system function.

In all cases, runtime checks each item for valid Key and Item parameter pairs. If the Key is null, or its matching description is null or an empty string, runtime throws an error and does not load that item. Also, to avoid duplicate items from appearing in the list, runtime does not load an item if it finds the item's Key parameter value in the combo box's current item list. This check avoids duplicate list items; however, it does not prevent two (or more) different list items with the same name (Description parameter) from appearing in the list.

No matter what method you choose to load the control, ensure that the user has at least one option to select. As part of the initialization process, if runtime cannot find at least one value to put in the drop-down list, it disables the combo box control until one or more values are loaded into the control.

In some cases, the values to load into the combo box might include an item where the Key is " " (single blank) and the description is "(None)." In fact, in JD Edwards EnterpriseOne applications, this value has been used as a blank default value, historically. Although this is a valid item to load into the combo box, it is recommended that you ascribe a meaningful text string to such an item that makes sense in the context of the application as opposed to descriptions such as (None), or " ."

Note: As of release 8.94, the practice of the runtime engine automatically loading a combo box that is configured in Form Design Aid (FDA) as being not required with a default combo box item of key = " " (single blank) and description = "(None)" is discontinued. If such an item must be loaded in the context of the application in question, that task is now the responsibility of the application developer to define and insert into the control.