Responding to Events in a Graphical User Interface
When you design a user interface, you are defining areas on your computer
screen, in the form of controls, that can generate events. For example, when you click on a command button, the button generates a user interface event that LabWindows/CVI then passes
to your C program. Actually, LabWindows/CVI controls generate multiple user
interface events. For example, a single mouse-click on a command button can pass
the following user interface events to your program for processing:
- GOT_FOCUS event—If the command button is not the active control (does not have the input
focus), a mouse-click on the button makes it the active control. When a control
receives the input focus, a GOT_FOCUS event occurs.
- LEFT_CLICK event—When users click with the left mouse button on the command button, a LEFT_CLICK event occurs. LabWindows/CVI user interface controls can recognize left,
right, single, and double mouse clicks.
- COMMIT event—When the user releases the mouse button, a COMMIT event occurs signifying that the user has performed a commit event on the
control.
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Note Each control can have one or more control modes that determine how the control responds to events. |