1. Getting started
2. Annotations
3. Dynamic resources
4. Validation
5. Form Elements
6. Actions
7. Environments
8. XML Forms

Actions

Actions are closely tied to forms and dialogs. They are declared by attaching [Action] attributes at desired locations.

Adding actions

Actions are added through the [Action] attribute. Actions have these properties:

• ActionName - a string that identifies the action. For example, "submit" and "cancel" are common values.
• Content - text content of rendered button.
• Parameter - any parameter you want to pass to the action handler. Accepts dynamic resources.
• IsEnabled - if this resolves to false, the button will be grayed out.
• IsLoading - while this resolves to true, the button will be replaced by a loading indicator.
• Icon - icon inside the action button.
• Validates - indicates whether the form should be validated when the action is performed. If validation fails the event will not propagate to handlers.
• ClosesDialog - indicates whether the action will close its hosting dialog.
• IsReset - indicates whether the action will reset the model to its default state.
• IsPrimary - indicates whether the action will display as a primary (raised) button.
• IsDefault - indicates whether the action can be performed with Enter key.
• IsCancel - indicates whether the action can be performed with Escape key.

Properties regarding layout are discussed in form elements.

Dialog actions

It is common to use actions only when the form is hosted in a dialog. For this reason you can use [DialogAction] attribute. DialogAction has IsVisible = {Env DialogHostContext} and ClosesDialog = true by default.

Handling actions

When an action is performed, an IActionContext is created and is passed to:

• Global action interceptors, which are registered in ActionElement.InterceptorChain.
• Local interceptor, which is set to ActionElement.ActionInterceptor.
• The form model, in case it implements IActionHandler.
• The form context, in case it implements IActionHandler.

IActionContext contains the following members:

• Model - model instance that contains the performed action.
• Context - form context at the time of invocation.
• Action - action identifier, usually ActionAttribute.ActionName.
• ActionParameter - resolved value of ActionAttribute.Parameter.
• ResourceContext - form’s associated IResourceContext. Usually this will also be an IFrameworkResourceContext which you can use to resolve the DynamicForm hosting the form.
• CloseFormHost() - closes form host when invoked. Useful when you have asynchronous action handling.

As noted above, both model and form context can handle actions. As a guideline, we suggest this pattern:

• Model instances should handle actions if they are directly related to their state, e.g. reset or validate fields.
• Context instances should handle actions that manage state outside of the model scope, e.g. save submitted form to database.
• Interceptors should listen to actions for logging, syncing with other plugins, etc.

Intercepting actions

You can write custom plugins or reusable logic and attach them to ActionElement.InterceptorChain or ActionElement.ActionInterceptor. An IActionInterceptor must implement IActionContext InterceptAction(IActionContext actionContext) which takes the current action context and can do things like:

• Perform side effects based on the action context.
• Return null to cancel action propagation to other handlers.
• Return a different IActionContext to allow proxying or injection.
• Return the original unmodified IActionContext and only “tap” the action event for side effects.