You can define which fields to display on the value help dialog by using the annotation @Common.ValueList. This is applicable to filter fields and the fields with value help in Edit and Create mode. For example, fields of a table in an object page, fields in sections or subsections.
Consider the following sample code:
123456789101112
annotate my.Booking {
to_Carrier @Common.ValueList: {
CollectionPath : 'Airline',
Label : '',
Parameters : [
{$Type: 'Common.ValueListParameterInOut', LocalDataProperty: to_Carrier_AirlineID, ValueListProperty: 'AirlineID'},
{$Type: 'Common.ValueListParameterDisplayOnly', ValueListProperty: 'Name'},
{$Type: 'Common.ValueListParameterDisplayOnly', ValueListProperty: 'CurrencyCode_code'}
]
};
}
In the sample code, for the entity Booking, the value help of the entity Airline has the value CollectionPath: 'Airline'. The first parameter of the entity Airline, maps the main entity property to_Carrier_AirlineID to the value help entity property AirlineID. The other two parameters, Name and CurrencyCode_code are a part of the entity Airline, and are of type Common.ValueListParameterDisplayOnly. They are used only for display in the value help dialog. The properties in Parameters of the type @Common.ValueList annotation are displayed in the value help dialog.

Let's familiarize the other three types of parameters.
Parameter type: Common.ValueListParameterIn
These parameters influence the filtering of value help of the annotated field.
Code Snippet123456789101112annotate my.Booking { ConnectionID @Common.ValueList: { CollectionPath : 'Flight', Label : '', Parameters : [ {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: to_Carrier_AirlineID, ValueListProperty: 'AirlineID'}, {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: ConnectionID, ValueListProperty: 'ConnectionID'}, {$Type: 'Common.ValueListParameterIn', LocalDataProperty: FlightDate, ValueListProperty: 'FlightDate'}, …. ] }In the preceding sample code, for the Booking entity, the annotated field is ConnectionID. The FlightDate is of the parameter type Common.ValueListParameterIn. It means that if a user has selected the flight date from the Flight Date field, then this value is used to filter the values displayed in the value help dialog for the Flight Number(ConnectionID) field.
Parameter type: Common.ValueListParameterOut
Code Snippet123456789101112annotate my.Booking { ConnectionID @Common.ValueList: { CollectionPath : 'Flight', Label : '', Parameters : [ {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: to_Carrier_AirlineID, ValueListProperty: 'AirlineID'}, {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: ConnectionID, ValueListProperty: 'ConnectionID'}, {$Type: 'Common.ValueListParameterOut', LocalDataProperty: FlightDate, ValueListProperty: 'FlightDate'}, …. ] }In the preceding sample code, for the Booking entity, the annotated field is ConnectionID. The FlightDate is of the parameter type Common.ValueListParameterOut. It means that if a user selects an airline from the value help dialog of the ConnectionID field, then the Flight Date field gets auto-populated with the corresponding value.
In contrast to the parameter type Common.ValueListParameterIn, this value isn't used to filter the value help dialog of the ConnenctionID field.
Parameter type:Common.ValueListParameterInOut
It is a combination of both In and Out parameter features.
Code Snippet1234567891011annotate my.Booking { ConnectionID @Common.ValueList: { CollectionPath : 'Flight', Label : '', Parameters : [ {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: to_Carrier_AirlineID, ValueListProperty: 'AirlineID'}, {$Type: 'Common.ValueListParameterInOut', LocalDataProperty: ConnectionID, ValueListProperty: 'ConnectionID'}, …. ] }In the preceding sample code, you can see that there is dependent filtering. For example, if you select the airline European Airlines (EA) from the Airline field, this value is set as a filter value for the Flight Number (ConnectionID) value help dialog and displays the flights for the selected airline only. This is the feature of the In parameter.
If a user selects a value from the value help dialog for the field ConnectionID, then the Airline field gets auto-populated with the corresponding entry. Similarly, if you select a flight number in the Flight Number, the Airline field gets auto-populated with the corresponding information.
