This display element is used to display on the screen a drop-down list and let the user choose one of a list of possible values.
Note the distinction between this element and Text Input Field, Number Input Field, etc. These allow the user to enter any input, while Chooser is used when the list of possible values is known in advance.
<Value> (non-repetitive element): The initial/selected value. Access it (to set its initial value or to retrieve the option that has been selected by the user) through a reference to the parent Chooser element or to a higher level display element containing it.
<Options> (repetitive element): The list of possible values that can be selected. Access it (to initiate the list of values that the user may choose from) through a reference to the parent Chooser element or to a higher level display element containing it.
<Empty Option Text>(non-repetitive element, not required): The text to display for the empty option, if one is required. If specified, the empty option will appear before the options specified in <Options>. If the user selects this option, <Value> will be empty.
Notice that <Value> and <Options> should be of the same type (e.g. both Text, both Date, or whatever data type you want). If they have a composite data type, the drop-down list diplays the first text field it contains. For example, if it contains a numeric field named Id and a text field named Name, then the Name values of each of the data structures in <Options> is diplayed.
You may add an action sub-model named <On Change> to model what should be done when the user selects an option. If you don't, nothing is done until another user action causes some action to be performed (e.g. pressing a Button).