By default, the IsExpanded property of each accordion pane is set to False, which means that the pane appears in its collapsed state when the page is loaded. If you want the pane to be expanded upon page load, you can set the IsExpanded property to True.

The following table illustrates the difference between the two expand states.

 

IsExpanded	Result
IsExpanded=False
IsExpanded=True

 

You can set the expand states in Design view, in XAML, or in code.