使用ArcGIS API for Silverlight 进行复合多条件空间查询

        //用于查询的Task
        QueryTask queryTask = new QueryTask();
        //查询的目标图层
        FeatureLayer featurelayer;

          //声明一个Draw,用于绘制查询的区域，进行空间查询
          Draw myDraw;

 public MainPage()
        {
            InitializeComponent();
            
            featurelayer = map1.Layers["RiverSourceLayer"] as FeatureLayer;

            editorWidget.Loaded += new RoutedEventHandler(editorWidget_Loaded);

            queryTask.Url = featurelayer.Url;
            queryTask.ExecuteCompleted += new EventHandler(queryTask_ExecuteCompleted);
            queryTask.Failed += new EventHandler(queryTask_Failed);

              myDraw = new Draw(map1);
              myDraw.DrawMode = DrawMode.Polygon;
              myDraw.IsEnabled = false;

              myDraw.FillSymbol = new SimpleFillSymbol()
              {
                BorderBrush=new SolidColorBrush(Colors.Black),
                BorderThickness=3,
                Fill=new SolidColorBrush (Colors.Red),
               };
              myDraw.DrawComplete += new EventHandler(myDraw_DrawComplete);

            FiledsCombox.ItemsSource = AttributeString.GraphicAttributesEnNameString;
        }

private void StartQueryBySQL(string sqlString)
        {
            if (ExpressionTextBox.Text == "")
                return;
            Query query = new Query();
            query.ReturnGeometry = true;
            query.OutFields.AddRange(AttributeString.GraphicAttributesEnNameString);
            query.Where = sqlString;
            query.OutSpatialReference = map1.SpatialReference;
            queryTask.ExecuteAsync(query);
        }

private void StartQueryBySpatial(ESRI.ArcGIS.Client.Geometry.Geometry geometry)
        {
            Query query = new Query();
            query.ReturnGeometry = true;
            query.OutFields.AddRange(AttributeString.GraphicAttributesEnNameString);
            query.Geometry = geometry;
            query.OutSpatialReference = map1.SpatialReference;
            queryTask.ExecuteAsync(query);
        }

  private void queryTask_ExecuteCompleted(object sender, QueryEventArgs e)
        {
            GraphicsLayer graphicsLayer = map1.Layers["QueryResultLayer"] as GraphicsLayer;
            graphicsLayer.ClearGraphics();

            if (e.FeatureSet.Features.Count > 0)
            {
                foreach (Graphic resultFeature in e.FeatureSet.Features)
                {
                    resultFeature.Symbol = new SimpleMarkerSymbol()
                        {
                            Color=new SolidColorBrush(Colors.Red),
                            Size=18,
                            Style=SimpleMarkerSymbol.SimpleMarkerStyle.Circle,
                        };
                    graphicsLayer.Graphics.Add(resultFeature);
                }
            }
            else
            {
                MessageBox.Show("没有查询到目标要素！");
            }
        }

private void myDraw_DrawComplete(object sender, DrawEventArgs e)
        {
            StartQueryBySpatial(e.Geometry);

            myDraw.IsEnabled = false;

        }