查询功能

来源：互联网发布：数据库系统概论课件编辑：程序博客网时间：2024/05/22 05:11

分类：1 图形查询属性（点击查询、多边形查询） 2 属性查询图形（单一属性查询，多种属性复合查询）

1.1点击查询

                IFeatureLayer pfeaturelayer = axMapControl1.get_Layer(0) as IFeatureLayer;   // 主要是确定要查找的图层
                IPoint point = new PointClass();                                                                                   // 点选查询，获取点信息
                point.PutCoords(e.mapX, e.mapY);
                ISpatialFilter spatialfilter = new SpatialFilterClass();                                               // ISpatialFilter两个关键参数分别为Geometry和SpatialRel
                spatialfilter.Geometry = point;
                spatialfilter.SpatialRel = ESRI.ArcGIS.Geodatabase.esriSpatialRelEnum.esriSpatialRelEnvelopeIntersects;  // 点与图层的关系
                IFeatureCursor FeatureCursor = pfeaturelayer.FeatureClass.Search(spatialfilter, false);
                IFeature feature;
                feature = FeatureCursor.NextFeature();

1.2 多边形查询

多边形查询分很多种包括矩形，圆形，多边形等等，其实主要方法还是一样的，与点击查询不同的是ISpatialFilter.Geometry不再是point

                IFeatureLayer pfeaturelayer=axMapControl1.get_Layer(0) as IFeatureLayer;
                IGeometry poylogn = axMapControl1.TrackRectangle() as IGeometry;
                ISpatialFilter spatialfileter = new SpatialFilterClass();
                spatialfileter.Geometry = poylogn;
                spatialfileter.SpatialRel = esriSpatialRelEnum.esriSpatialRelEnvelopeIntersects;
                IFeatureCursor cursor = pfeaturelayer.FeatureClass.Search(spatialfileter, false);
                IFeature pfeature = cursor.NextFeature();

2.1属性查询图形

主要用的接口为IQueryFilter接口，查询是属性为Double和String 的时候还是有区别的，比如：

属性为string的时候地块编号=’01A’

属性为double的时候地块面积=100；

            string test = textBox6.Text;
            IFeatureLayer featurelayer = axMapControl1.get_Layer(0) as IFeatureLayer;
            IQueryFilter filter = new QueryFilterClass();
            filter.WhereClause = "地块编号='" + test + "'";
            IFeatureCursor featurecursor;
            featurecursor = featurelayer.FeatureClass.Search(filter, false);
            IFeature feature;

当然属性查询图形还有一个必要的功能是，能够定位到图形。