如何为 Windows Phone 8 请求行车或步行路线

        async void RequestDirections()
        {
            // Get the values required to specify the destination.
            string latitude = "47.6451413797194";
            string longitude = "-122.141964733601";
            string name = "Redmond, WA";

            // Assemble the Uri to launch.
            Uri uri = new Uri("ms-drive-to:?destination.latitude=" + latitude + 
                "&destination.longitude=" + longitude + "&destination.name=" + name);
            // The resulting Uri is: "ms-drive-to:?destination.latitude=47.6451413797194
            //  &destination.longitude=-122.141964733601&destination.name=Redmond, WA")

            // Launch the Uri.
            var success = await Windows.System.Launcher.LaunchUriAsync(uri);

            if (success)
            {
                // Uri launched.
            }
            else
            {
                // Uri failed to launch.
            }
        }