Marker dragging and do not changing lat lng position

Question

what I'm doing wrong.

I try to put a Marker and enable the Drag property, so I can get Lat and Lng coordinates, but, if I move the Marker with the mouse to an other place on the map, this values of geolocation (Lat and Lng) remain the same.

To get these values from my Marker, I'm using this code:

gmapMarcador.Items[0].Position.Lat
gmapMarcador.Items[0].Position.Lng