org.apache.tapestry5.corelib.components.Form.xdoc Maven / Gradle / Ivy
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The following components are Tapestry wrappers around client-side HTML form elements:
Examples of the Form component are provided in the many
other pages that discuss specific form control element components,
such as
Radio
andTextField.
The Form component generates a seemingly bewildering number of
events, designed to address a wide range of needs. The goal
is to give you as the developer the tools necessary to
effeciently manage state.
All of the events that are triggered will pass along
the values defined by the context parameter. Most often,
there is no context, or the context is a single value
(a primary key used to identify the object being updated
by the form).
Render event handler methods should
not
return a value, doing
so will be an error. The methods are intended to allow
the page to convert a primary key stored in the context
back into an object ready to have its properties updated
by the Form.
The context passed to component event handler methods is provided by reading the context parameter.
- prepareForRender
- prepare
Submit events may return a navigational value, which will
abort any remaining processing of the form submission.
The context provided to component event handler methods
originates in the form submission (it is stored in hidden form fields); the
context parameter is
not
read during a form submission.
- prepareForSubmit
- prepare
- validate
- validateForm (deprecated)
- failure
or
success
- submit
The validate event is to allow the page to
perform cross-field validation. The validateForm event is a deprecated name for the
validate event (it currently exists only for backwards compatibility).
The failure or success
event is fired based on whether there are or are not any
validation errors.
It is considered a best practice to give explicit ids to
Form components, and form control element components.
These ids propagate down to the client side as
element names and/or ids, and eventually show up
as query parameters when the form is submitted.
To achieve a more RESTful URL scheme, give the form component
an id based on what it does rather than what data it updates, thus
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rather than
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or
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