At times, application developers may be unsure what control/object to add to a form, when end users are requesting a menu to select from a list of preset values. Based upon how the list of information is to be displayed, where the list of available data resides, and if the selected item will be stored or only captured, there are different form control types that can be used to display the perfect option to the users.
Control Display
The type of control to add to a form depends on the amount of available space on the form and how the list of information is to be presented to the users.
When limited space is available on forms, a "Combo Box" control is ideal, as the list of options to select is "dropped down" and visible when the control is selected.
If space is not a factor, "List Box" and "List View" controls are available to present a box-type object with a list of selections initially displayed. The List Box presents the list of data to select in a single column, and perhaps separated. The List View presents a list of data selections in multiple columns within a grid-like display. The objects consume a larger amount of space but can be sized accordingly.
When the content within the Combo Box, List Box, or List View is larger than visible listing, a scroll bar is available to browse further content.
Source of Data to Select
The source of data populating the control will determine the type of control. If the source is stored within a table, a "Lookup" control is to be used. Otherwise, if the list of options will be manually added and stored within the control, a "User Defined" control is used. A User Defined control can contain a small selection of items (e.g. Yes, No, Maybe) or a large list. In most cases, a "Lookup" control is assigned.
End Result for Selection
Another factor to decide what control to use is the "end result" to take after the item, or items, is selected by the user. If the selection is to be stored directly into a table, the "DB" control is used. If the selection must be captured into a variable, use the "Variable" type control.
Controls and Examples of Use
DB Lookup Combo Box - Displays a drop-down menu list of data pulled from a table. The selection is stored in another table. An example is a list of job titles that can be assigned to employees. The titles are stored in a different table than the employees.
DB Lookup List Box - Displays a box of listed data pulled from a table. The selection is stored in another table. An example is a list of vendors that can be assigned to an order. The vendors are stored in a different table than the orders.
DB User Defined Combo Box - Displays a drop-down menu list of options defined and stored within the control. The selection is stored in a table. An example is a drop-down menu of predefined answers for a questionnaire.
DB User Defined List Box - Displays a box of listed data defined and stored within the control. The selection is stored in a table. An example is a full displayed list of predefined answers for a questionnaire.
DB Lookup List View - Displays a grid of listed data pulled from a table. The selection is stored in a table. An example is a grid of companies, with the city and state aligned in separate columns, that can be assigned to an order. The company data is stored in a different table than the orders.
Variable Lookup Combo Box - Displays a drop-down menu list of data pulled from a table. The selection is captured into a defined variable. An example is a drop-down menu of employees where the selection is used in further form processing.
Variable Lookup List Box - Displays a box of listed data pulled from a table. The selection is captured into a defined variable. An example is a list of dates where transactions occurred for a specific month where the selection is used in further form processing.
Variable User Defined Combo Box - Displays a drop-down menu list of options defined and stored within the control. The selection is captured into a defined variable. An example is a drop-down menu of print output options used in report processing.
Variable User Defined List Box - Displays a box of listed data defined and stored within the control. The selection is captured into a defined variable. An example is a list of available reports used in report processing.
Variable Lookup List View - Displays a grid of listed data pulled from a table. The selection is captured into a defined variable. An example is a grid of transactions, with details of quantity, prices, etc., aligned in separate columns. The selection is used in further form processing.
Additional Controls
Many other control types are available and can be added to R:BASE forms based upon the data presented to users. Be sure to review the other available controls to provide the best available appearance of the displayed data.
