In the following sections, we'll look at the Subscribe element. We covered several subscribable control events in the last chapter, including those used by the SelectionTree and ProgressBar. We'll take a look at some others that we missed.
You can subscribe a Text control to the ScriptInProgress event so that its text is only shown during the "immediate" phase of InstallExecuteSequence. This is when that sequence prepares itself for its "deferred" stage by creating a rollback script containing all of the actions it will need to perform.
You'd use this technique on a progress bar dialog. As you can see in the following example, all it does is show some text telling the user that things are gearing up:
Here, we have a dialog called ProgressDlg that is shown during InstallExecuteSequence. It contains the following markup:
<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Fragment>
<UI>
...