ArcGIS for SilverLight 线要素缓冲分析的问题

在网上搜索上N多的示例，都告诉我们，例如我想将一个要素扩边4米，得做缓冲分析代码大至如下：

var geoservice = new Geometryservice(geoserviceUrl);
geoservice.bufferCompleted +=
    (sender,args) =>
        {
            geo = args.Results[0].Geometry;
            QueryListByGeometry(geo,objLayerUrl,objWhere,objField,intersect,handler);
        };
geoservice.Failed += (sender,args) =>
                         {
                             message = String.Format("Step 2 Failed: {0}",geoLayerUrl);
                             handler(null,messagE);
                         };
var bufferParams = new BufferParameters
                       {
                           BufferSpatialReference = geo.SpatialReference,OutSpatialReference = geo.SpatialReference,Unit = LinearUnit.Meter
                       };
bufferParams.Distances.Add(4);//扩展4米
bufferParams.Features.Add(new Graphic{ Geometry = geo });
geoservice.bufferAsync(bufferParams);

如果是线要素做扩展，以上代码是不可能得到你想结果的，得这么做

//bufferParamS.Unit = LinearUnit.Meter;
bufferParams.Distances.AddRange(new double[] { 0.00035,0.00035 });//0.00035约等于4米