Charles has developed a Windows Store app named MyToDo, which allows users to maintain a to-do list. It allows the users to add or delete the tasks to be performed.

Charles has developed a Windows Store app named MyToDo, which allows users to maintain a
to-do list. It allows the users to add or delete the tasks to be performed.
The tasks added by the users are displayed on the right of the UI. Now, Charles wants to add a
functionality that enables the users to store all the tasks added in the app in a single plain text
format file named ToDo.txt in Documents Library. The button, Save to File, is provided on the
App bar, which allows the users to save the tasks added in the list to the ToDo.txt file. Charles
writes code to accomplish these requirements of the app. However, on the click of the Save to
File button, the tasks are not saved in the file.
Help Charles to identify the reason and suggest a solution.

Solution;

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