Below is a sample code snippet that demonstrates How to Get Directions in Map in Windows Phone 8 using C#? The Start point is not specified for the MapsDirectionsTask object and hence takes the users current location.
How to Get Directions in Map in Windows Phone 8 using C#?
MapsDirectionsTask task = new MapsDirectionsTask();
task.End = new LabeledMapLocation("Anna Salai", null); ;
task.Show();