Here is the link to the sample:
ArcGIS API for Silverlight - Interactive Samples | ArcGIS for Developers
I would like to know, how does the geometry service calculate the length. I mean, if there is the shortest distance between a polyline vertex and the click point returned?
When using ESRI .NET SDK you have got the GeometryEngine.NearestCoordinate function. It returns the nearest coordinate on the geometry, but in Silverlight you get only the distance and there is unknow, if the distance is between the click point and the nearest vertex or between the click point and the nearest coordinate on the geometry.
