2.27.1 Correct Use of Controls

There are a number of conventions on the use of the different Windows interface controls. These conventions are based on the functionality of the control. For example you would quite naturally visualize an action or a command as a command button.

Often you will have a choice of several controls for visualizing a component. In deciding which is the most appropriate one look for the one which will do most to simplify the interface of your program. Also consider the other controls which have been placed on the form, so as not to have, for instance, more than one tree view in a window

Think about the Purpose of the Control

Broadly speaking controls have the following purposes:

Action	Push button Toolbar button Menu option
Entry, display and selection	List view, list box and combo box Grid Tree view Check box and radio button Edit box, spin edit, track bar
Feedback	Status bar and progress bar
Grouping	Tab sheet, group box

How Do I Represent a… ?

The following guidelines are meant to help you choose the right visualization style for various situations. They are not absolute.

Choice between two options

Notice how differently data and logic are represented:

Database Data (Fields) Program Logic (Actions) To record a Yes/No choice in the data base, make the field's visualization style Check box. To record a choice of one of two values in the data base, make the field's visualization style Radio button. To let the user choose from two actions, use two buttons. Or use a menu.

Choice between several options

Again, notice how differently data and actions are shown:

Database Data (Fields) Program Logic (Actions) To record an user's choice of a value for a field, make the field's visualization style Picklist. The picklist's appearance can be: A set of radio buttons in a frame A list box A drop-down list To let the user choose from several items or actions, use a list with a set of buttons Or use a menu for several items: Or for several actions:

 

There Are Only Three Ways for the User to Trigger an Action

In GUI applications there are only three correct controls you can use to let the user trigger an action:

• A push button

• A menu option

• A toolbar button

In standard GUI usage these three controls command immediate action. No other control has this characteristic.

Do not, for example, trigger an action when the user ticks a check box (except to write the choice to a database). This is because a check box is universally used to present a yes/no selection, not an action.

Let's say your application brings up a new window if the user decides to create a new invoice. It would be wrong to represent this as a check box, because the user does not expect a new window to appear when they tick a box:

For your application to behave predictably, you represent this choice as:

 

	A push button
	A menu option
	A toolbar button