TaskDialogExpander.Expanded Property   
Definition
Important
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Gets or sets a value that indicates whether the expander button is in the expanded state (so that the dialog's expanded area is visible).
public:
 property bool Expanded { bool get(); void set(bool value); };public bool Expanded { get; set; }member this.Expanded : bool with get, setPublic Property Expanded As BooleanProperty Value
true if the expander button is in the expanded state; false if it's in the collapsed state. The default value is false.
Exceptions
The property is set and this expander instance is currently bound to a task dialog.