Event-to-action connections cause an action to be performed when a certain event takes place. The default color of this connection type is green.

For event-to-action connections, the event is always the source and the action is always the target. If you try to connect an action to an event, VA Smalltalk automatically reverses the source and target for you, so the connection is an event-to-action. A simple example of an event-to-action connection follows:

This causes a second window to display when the push button is pressed.

Attributes can also be used to trigger an action and events can be used to change the value of an attribute. This behavior is made possible because an attribute typically signals when it is changed. As a result, you can make the following connections with attributes:

When an attribute value has changed, it can be used to cause an action to be performed. A simple example of an attribute-to-action connection follows:

The push button will become enabled as soon as a user types text into the Text part.

An event can be used to set an attribute value. In this case, a parameter must be used with the connection to supply the attribute value. A simple example of an event-to-attribute connection follows:

When the window is opened its title text will be set to This is a window title. This example is rather contrived, but it conveys the idea. For more information, see Connection parameters.