Charles has been assigned a task to develop the WritingPad app. He has created the interface of the app, as shown in the following figure.

Charles has been assigned a task to develop the WritingPad app. He has created the interface of
the app, as shown in the following figure.
The Interface of the App

The app contains a text box, where a user can type content. In addition, it must keep the data
provided by the user, even if it is terminated by the user or OS.
For this, Charles uses the LocalSettings property of the ApplicationDataContainer object to keep
the text box content. Further, the content from the LocalSettings property of the
ApplicationDataContainer object will be retrieved in the OnNavigatedTo() method. However, when
Charles executes the app, it throws an exception.
Help Charles to identify the reason and the solution to the problem.

Solution;

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