The PickParamAlt animation property can only be used when the button style is Latched. It allows a pick action menu (or specific pick action) to be associated with the button when it appears to be pressed down. The PickParam property allows a pick action menu to be associated with a the button when it appears to be raised.
The PickParamAlt property can be animated in exactly the same way as the PickParam property—the only difference is that the action or menu that you associate with the PickParamAlt property will only be applied or made available when the button appears to be pressed down. The action or menu that is used to animate the PickParam property, if any, will apply when the button appears to be raised.
Example:
A latched button is used to Hand Control a digital point named 'Button States'. When the button is pressed, the point is hand controlled to be in State 1 and when the button is selected again (raised), the point is hand controlled to be in State 0. To achieve this, the following animations are setup:
The Latched property is animated by the CurrentState of the digital point so that it appears pressed down or raised according to the current state of the point. The following expression is used:
".Button States.CurrentState"
The PickParam property is animated so that when the button is raised (not pressed down), the digital point is hand controlled to State 0. The expression for the PickParam property is:
".Button States.ObjectLink" + '?CurrentState&Value="1"'
The ".Button States.ObjectLink" part of the expression associates the raised button with the pick action menu for the 'Button States' digital point, and the '?CurrentState&Value="1"' part of the expression associates the raised button with the Hand Control action (CurrentState) which sets the value of the digital point to State 1.
The PickParamAlt property is animated so that when the button is pressed down, the digital point is hand controlled to State 1. The expression for the PickParamAlt property is:
".Button States.ObjectLink" + '?CurrentState&Value="0"'
The ".Button States.ObjectLink" part of the expression associates the pressed down button with the pick action menu for the 'Button States' digital point, and the '?CurrentState&Value="1"' part of the expression associates the pressed down button with the Hand Control action (CurrentState) which sets the value of the digital point to State 0.
The Text property has the following expression:
".Button States.CurrentStateDesc"
This associates the current state description of the 'Button States' point with the text that is shown on the button. This means that when the button is pressed down, the text will show 'State 1' and the 'Button States' digital point is hand controlled to be in State 1. When the button is reselected so that it becomes raised, the button text changes to 'State 0' and the 'Button States' digital point is hand controlled to be in State 0.
The effect of the PickParam and PickParamAlt animations can also be achieved by using the Pick Action Wizard for the button.
After selecting Method as the type of pick action, you can use the next two 'pages' of the Wizard to setup the action that is performed and the value that is set when the button is up (raised) or down (pressed down).
