The DataHolder component (Flash Professional only)

The DataHolder component is a simplified version of the DataSet component whose only purpose is to hold data. It can be used as a connector between components. It communicates with other components via data binding. Initially the DataHolder component has a single bindable property, data. The user can add more properties, using the schema panel, if desired. The DataHolder component has no runtime visual appearance.

Every bindable property of the DataHolder component, including the built-in property data or any other property you add, works as follows: you can assign any type of data to a DataHolder property, either through data binding or using your own ActionScript code. Whenever you do, the DataHolder component emits an event whose name is the same as the property, and it executes any bindings if appropriate.

In most cases, you will not use this component to build an application. It is needed only when, for some reason, you cannot bind external data directly to another component and you do not want to use a DataSet component. Here are some situations in which you would use the DataHolder component:

• For a data value that is generated by ActionScript code but that you want to bind to some other component. For this case, you could have a DataHolder component that is databound as required; your ActionScript code can assign new values at any time to the component, and these values will be distributed.
• For a data value that can come (via data binding) from several sources (for example, several web services that all return the same kind of query result). In this case you could bind data from all the sources to the DataHolder component and then bind from the DataHolder component to the UI components that are displaying the data.
• For a data value that results from a complex, indexed data binding, as in the following schematic diagram. In this case, it is convenient to bind the data value to a DataHolder component and then use that for bindings to the UI.

  

Note: The DataHolder component is not meant to implement the same control over your data as the DataSet component. It does not manage or track data, or have the ability to update data. It is a repository for holding data and generating events when that data has changed.