线做缓冲区buffer出现null的解决办法

GeometryService geometryService =               new GeometryService("http://tasks.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");                             geometryService.BufferCompleted += GeometryService_BufferCompleted;                             geometryService.Failed += GeometryService_Failed;

                            BufferParameters bufferParams = new BufferParameters()                             {                                 Unit = LinearUnit.StatuteMile,                                 BufferSpatialReference = new SpatialReference(3395),                                 OutSpatialReference = myMap.SpatialReference,                                 //UnionResults = true

                            };                             Graphic graphic = new Graphic()                             {                                 Symbol = LayoutRoot.Resources["DefaultLineSymbol"] as Symbol,                                 Geometry = mercator.FromGeographic(polylines)                                 //Geometry = mercator.FromGeographic(new MapPoint(531698.0432, 3344026.7482))                             };                             bufferParams.Features.Add(graphic);                             bufferParams.Distances.Add(ErrorValue);//ErrorValue/6378137.0*180.0/Math.PI                                                         geometryService.BufferAsync(bufferParams);

 

需要将BufferSpatialReference坐标系设置为3395，也有网友说要将UnionResults = true不能写，但我试了，也是有值的