Point in Polygon *On a map*

Question

I'm using Visual Studio 2010, including reference Dynamic Data Display map. I'm drawing on the map polygon by drawing DragglePoints and Segments between the points. I found a code that find if point(x,y) is in polygon, but on a map it doesnt work.

 pt = e.GetPosition(this.plotter.CentralGrid); // Get the mouse position
 ps = this.plotter.Viewport.Transform.ScreenToViewport(pt); // Transform the mouse positon to Screen on chartplotter

// Now ps is the point converting to the map point - it works perfect
// I'm using it for another things.(like Painting a dragglepoint or something else.

for (int k = 0; k <= listPolygons.Count - 1; k++)
{
   bool ifInside = PointInPolygon(new Point(ps.X, double.Parse(this.plotter.Viewport.Transform.DataTransform.ViewportToData(ps).Y.ToString())), listPolygons[k]); // Sending to the functing pointInPolygon the point and list of polygons we have
   if (ifInside)
   {
       listPolygons[k].removePolygon(listPolygons[k], plotter);
       listPolygons.RemoveAt(k);
       break;
   }
}

and the function PointInPolygon:

private bool PointInPolygon(Point point, Polygon polygon) 
{
    List<DraggablePoint> points = polygon.getListPoints();
    DraggablePoint pointClicked = new DraggablePoint(new Point(point.X, point.Y));
    int i, j, nvert = polygon.getNumberOfVertx();
    bool c = false;

    for(i = 0, j = nvert - 1; i < nvert; j = i++)
    {
        if (((points[i].Position.Y) >= pointClicked.Position.Y) != (points[j].Position.Y >= pointClicked.Position.Y) &&
                (pointClicked.Position.X <= (points[j].Position.X - points[i].Position.X) * (pointClicked.Position.Y - points[i].Position.Y) / (points[j].Position.Y - points[i].Position.Y) + points[i].Position.X))
                c = !c;
    }

    return c;
}

Here c always returns as false, whether I click inside a polygon or outside. points[i].Position.Y and points[i].Position.X and pointClicked.Position.Y and pointClicked.Position.X is given a perfect variables - on the map values.