GIS二次开发之查询

      最近做B/S的项目，实在是有点忙，虽然感觉没什么难度，可是复杂的流程和巨大的工作量还是很无奈。上班时间根本没有时间再学习GIS，所以只好下班回去简单的学习一下。本来上讲中提到这讲会介绍MapTOCControl的右击菜单，哈哈，这个暂时没整理好，还是先看看GIS的查询吧。哈哈。

     老规矩，有图有真相，看看效果图。

     在GIS中查询分为：属性查询和空间查询，分别对应的接口是IQueryFilter和ISpatialFilter，当然后者继承了前者。

     在效果图中，用鼠标点击地图弹出BalloonCallOut的是利用空间查询实现的，在右边的查询条件中点击查询按钮实现的定位查询是属性查询。（哈哈，我想大家一看就知道了。）

     ①：属性查询代码：

       #region 属性查询
        private void btnSearchCity_Click(object sender, EventArgs e)
        {
            IActiveView pActiveView = axMapMain.Map as IActiveView;
            IGraphicsContainer pGrahpicsContainer = pActiveView as IGraphicsContainer;
            //先清除
            pGrahpicsContainer.DeleteAllElements();
            axMapMain.Extent = pActiveView.FullExtent;
            axMapMain.ActiveView.ScreenDisplay.UpdateWindow();

            IFeatureLayer pFeatureLayer = axMapMain.get_Layer(1) as IFeatureLayer;
            if (null == pFeatureLayer) MessageBox.Show("选择图层不是Feature图层");
            IQueryFilter queryFilter = new QueryFilterClass();
            queryFilter.WhereClause = "Name='" + this.cbCity.Text + "'";
            IFeatureCursor featureCursor = pFeatureLayer.Search(queryFilter, false);
            IFeature pFeature = null;
            while ((pFeature = featureCursor.NextFeature()) != null)
            {
                axMapMain.FlashShape(pFeature.Shape);
            }
        }
        #endregion

      ②：空间查询

       #region 几何查询
        private void axMapMain_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e)
        {
            IFeatureLayer pFeatureLayer = axMapMain.get_Layer(1) as IFeatureLayer;
            if (null == pFeatureLayer) return;

            IPoint point = new PointClass();
            point.X = e.mapX;
            point.Y = e.mapY;

            ISpatialFilter spatialFilter = new SpatialFilterClass();
            spatialFilter.Geometry = point;
            spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;

            IFeatureCursor featureCursor = pFeatureLayer.Search(spatialFilter, true);
            IFeature pFeature = featureCursor.NextFeature();

            while (pFeature != null)
            {
                int index = pFeature.Table.FindField("Name");
                string name = pFeature.Table.GetRow(pFeature.OID).get_Value(index).ToString();
                AddBalloonCallout(e.mapX, e.mapY, name);
                axMapMain.FlashShape(pFeature.Shape);
                pFeature = featureCursor.NextFeature();
            }

            System.Threading.Thread.Sleep(1000);
            IActiveView pActiveView = axMapMain.Map as IActiveView;
            IGraphicsContainer pGrahpicsContainer = pActiveView as IGraphicsContainer;
            pGrahpicsContainer.DeleteAllElements();
            axMapMain.ActiveView.ScreenDisplay.UpdateWindow();
            pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
        }
        #endregion