in Windows Phone 8 I need when iam in the range of 1km from a specific point i see a toast notification

Question

I need in WP 8 when a device be in the range of specific point (say 1km range) the application shown a toast notification tell me that am near this place.

Answer 1

You should fix a set of coordinates, latitude and longitude which is your specific point. You have the position changed event for the geolocator which you can handle.

like here:: http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj247548(v=vs.105).aspx

Once you have that working, you can calculate distance between two locations as shown here,

Calculating Distance between two Latitude and Longitude GeoCoordinates

And you can show any pop up on the screen if you find that the distance is greater than or equal to 1km. Hope that helps.