Automatic and Explicit Context Updates

Supported context management methods include both automatic and explicit context updates.

Automatic updates – use data that is passed from another tile when a navigation action occurs. You can pass BO attributes, references to context or global context data, or to free text. Use $_context.<attribute> to refer to an existing local context attribute, and $_global.<attribute> for a global context attribute. This example shows how context parameters are passed when the navigate action is triggered. The target tile’s (TileB) local context is updated with the two values: a free text and a value coming from a binding:

<UIElement type="button">
  <P pid="text" value="Go" />
  <P pid="halign" value="center" />
  <Event eventId="onClick">
    <Action actionId="navigate">
     <!--Context receiver – the target tile which receives the context upon navigating to it -->
      <P pid="target" value="TileB" />     
     <!-- Keys and values to be passed to the target Tile's local context -->
	 <!-- The freetext value "Tablet" is passed for the key "type" -->
      <P pid="type" value="Tablet" />
	 <!-- The movie title coming from the binding MovieTitles is passed for the key "movie" -->
	  <P pid="movie" value="{$MovieTitles.Name}"	  
    </Action>
  </Event>
</UIElement>

Explicit updates – use updateContext action to update the local context of tiles that appear on the same screen or exist in the tile stack.
You must specify the target tile (the receiver) in the same way as for automatic updates. Similarly, define the key-value pairs to be passed to the target tile as properties. You can pass BO attributes, references to local or global context data, or to free text. Use $_context.<attribute> to refer to an existing local context attribute, and $_global.<attribute> for a global context attribute. To pass the same objects to several different tiles, add a new updateContext action for every tile and repeat the context parameters. This example demonstrates how to bind the updateContext to the onClick event of a button. When the device user taps the button, the Tile3 target tiles’s context is updated for the “platform” and “type” keys.
```
<UIElement type="button">
 
 
 <Event eventId="onClick">
 <Action actionId="updateContext">
 <!—Context receiver – the target tile which receives the context-->
 
 <!—the key and value to be updated -->
 
 
 <!—the key and value to be updated – value is free text in this case-->
 
 </Action>
 </Event>
</UIElement>
```