Tasks URI Scheme
From version 1.81 the Tasks app supports a custom Uri scheme allowing you to programmatically perform functions from your own app. This is defined in the tasks: scheme detailed below:-
tasks: Launch the Tasks application to the main page
tasks:new Launch the New Task dialog with default values
Optional parameters:
subject - The new Task subject
details - The contents of the notes field (plain text)
start - The start date in local time in the form yyyyMMdd
due - The due date in local time in the form yyyyMMdd e.g. fully escaped the Uri appears as:-
tasks:new?subject=New%20Year&due=20131231&details=Have%20a%20party
Additionally we have created a library on NuGet to handle the Uri creation and activation for you - http://inthehand.uservoice.com/knowledgebase/articles/350182-tasks-api-for-windows-phone