Apple WebObjects 3.5 Manual de usuario descargar pdf (Pagina 82)

Chapter 3 Creating a WebObjects Database Application

Bindings in the Query Part

In the query part of the component, movieDisplayGroup.queryMatch.title is bound to the

Title text ﬁeld. There are similar bindings to the Category and Rating text

ﬁelds. The

queryMatch bindings allow users to specify search criteria to use when

movieDisplayGroup next fetches movies. The Match button is bound to

movieDisplayGroup.qualifyDataSource, which actually performs the fetch.

For example, to display only R-rated comedies, a user types “Comedy” in the

Category text ﬁeld, types “R” in the Rating text ﬁeld, and clicks the Match

button.

movieDisplayGroup then refetches, selecting only movies whose category

values are set to Comedy and whose

rating values are set to R.

Bindings in the Repetition Part

In the repetition part of the component where matching movies are listed,

movieDisplayGroup.displayedObjects is bound to a repetition. More speciﬁcally,

displayedObjects is bound to the repetition’s list attribute, providing a vector

of movies for the repetition to iterate over.

The

movie variable is bound to the repetition’s item attribute to hold each movie

in turn, and

movie.title is bound to the string element inside the repetition. These

bindings produce a list of movie titles.

The repetition’s string element is enclosed in a hyperlink. By clicking a movie

title, the user selects the corresponding movie.

Displays the binding for the

repetition’s

list attribute.

Displays the binding for the

repetition’s

item attribute.

Displays the binding for the

string’s

value attribute.

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Apple WebObjects 3.5 Manual de usuario Pagina 82