ArcEngine|空间查询功能
所有的代码已经传到了我的GitHub，需要的请自取，GitHub项目地址：https://github.com/Weltra/T_ArcMap
（1）界面设计
（2）思路
就实现细节而言，实例通过ISpatialFilter 接口来定义空间查询条件，其Geometry属性确定用来查询的空间几何体， SpatialRel属性定义查询所使用的所有空间关系，为esriSpatialRelEnum 枚举类型的变量。包括：esriSpatialRelIntersects（空间相交）、esriSpatialRelTouches（空间相接——共享空间边界）、esriSpatiaIReIOverlaps（空间覆盖）、esriSpatialRelCrosses （ 空间跨越）、esriSpatiaIReIWithin（空间被包含）、esriSpatialRelContains （空间包含）等。因为ISpatialFilter 接口继承于IQueryFilter 接口，因此在定义好空间查询条件后，可以使用IQueryFilter 接口的查询方法进行空间查询操作。另外，在合并源图层的几何体时，使用ITopologicalOperator 接口的Union方法来进行几何体合并操作，该接口是点、线、面等几何体对象所共同实现的接口。
最后在【根据空间位置选择】窗体中完成空间查询功能。在DataGrid view中显示出查询结果。
（3）代码实现
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
namespace TArcMap.GeoProcessing
{
public partial class SpatialQueryForm : Form
{
private List<IFeatureLayer> _layers = new List<IFeatureLayer>();
public IFeatureLayer TargetLayer { get; set; }
private IMap _IMap;
private ICursor ResultCursor { get; set; }
public ISpatialFilter SpatialFilter
{
get;
set;
}
public SpatialQueryForm()
{
InitializeComponent();
}
public SpatialQueryForm(IMap map)
: this()
{
this._IMap = map;
IEnumLayer layerInterator = map.Layers;
layerInterator.Reset();
ILayer tmpLayer = layerInterator.Next();
while (tmpLayer != null)
{
//checking the layer type is the Feature layer
if (tmpLayer is IFeatureLayer)
{
IFeatureLayer tmpFeatureLayer = tmpLayer as IFeatureLayer;
this._layers.Add(tmpFeatureLayer);
tmpLayer = layerInterator.Next();
}
}
this.SpatialFilter = new SpatialFilter();
//set the layer name
this.initializeControlItems();
}
private void initializeControlItems()
{
if (this._layers != null && this._layers.Count > 0)
{
for (int i = 0; i < this._layers.Count; i++)
{
//add to the target list
this.comboBox_targetLayer.Items.Add(_layers[i].Name);
//add to the sources list
this.comboBox_SourceLayer.Items.Add(_layers[i].Name);
}
}
this.comboBox_spRelation.DataSource = Enum.GetNames(typeof(esriSpatialRelEnum));
}
/// <summary>
/// 1.根据提供的图层名称，找到对应 FeatureLayer；
/// 2.将对应的FeatureLayer中所有的Feature填充到GeometryBag中，作为返回值；
/// </summary>
/// <param name="layerName">图层名称</param>
/// <returns>图层中所有的要素组成的GeometryBag</returns>
private GeometryBag extractSourceGeometry(string layerName)
{
IFeatureLayer sourceFeatureLayer = GetLayerByName(layerName);
//新建立一个GeometryBag将所有的FeatureClass中的Geometry作为查询的source。
GeometryBag geometryBag = new GeometryBag();
IGeometryCollection geometryCollection = geometryBag as IGeometryCollection;
//提取FeatureLayer中的FeatureClass，提取其中的sp并赋值给GeometryBag
IGeoDataset sourceGeoDataset = (IGeoDataset)sourceFeatureLayer.FeatureClass;
ISpatialReference spRef = sourceGeoDataset.SpatialReference;
geometryBag.SpatialReference = spRef;
//提取FeatureClass中的每个Feature并添加到GeometryBag中。
IFeatureCursor soruceFeatureCursor = sourceFeatureLayer.Search(null, false);
IFeature pFeature = null;
object missingType = Type.Missing;
while ((pFeature = soruceFeatureCursor.NextFeature()) != null)
{
geometryCollection.AddGeometry(pFeature.Shape, ref missingType, ref missingType);
}
//设置GeometryBag中的空间索引，优化检索速度。
ISpatialIndex spatialIndex = (ISpatialIndex)geometryBag;
spatialIndex.AllowIndexing = true;
spatialIndex.Invalidate();
return geometryBag;
}
/// <summary>
/// 根据图层名称在this._layers中找到对应的FeatureLayer
/// </summary>
/// <param name="layerName">string：提供图层名称</param>
/// <returns>IFeatureLayer:返回矢量图层</returns>
private IFeatureLayer GetLayerByName(string layerName)
{
IEnumerable<IFeatureLayer> sourceLayers = from IFeatureLayer layer in _layers
where layer.Name == layerName
select layer;
List<IFeatureLayer> sourceLayerList = sourceLayers.ToList();
IFeatureLayer sourceFeatureLayer = sourceLayerList[0];
return sourceFeatureLayer;
}
private esriSpatialRelEnum extractSpRelation(string spRelationName = "esriSpatialRelIntersects")
{
//Enum.Parse(typeof(esriSpatialRelationEnum), spRelationName);//不稳定；
esriSpatialRelEnum spRelation;
if (Enum.TryParse(spRelationName, out spRelation))
{
return spRelation;
}
else
{
return esriSpatialRelEnum.esriSpatialRelIntersects;
}
}
private void button_buildSpFilter_Click(object sender, EventArgs e)
{
//1 提取筛选用图层，转换为GeometryBag
GeometryBag geometryBag = this.extractSourceGeometry(this.comboBox_SourceLayer.SelectedItem.ToString());
esriSpatialRelEnum spRelation = this.extractSpRelation(this.comboBox_spRelation.SelectedItem.ToString());
//构造SpFilter
this.SpatialFilter.Geometry = geometryBag;
//SpatialFilter.GeometryField = pInputFeatureLayer.FeatureClass.ShapeFieldName;
this.SpatialFilter.SpatialRel = spRelation;
//SpatialFilter.SpatialRelDescription = overlap_typestring;
//SpatialFilter.SubFields = "shape";
this.TargetLayer = this.GetLayerByName(this.comboBox_targetLayer.SelectedItem.ToString());
if (this.SpatialFilter != null && this.TargetLayer != null)
{
IFeatureCursor featureCursor = this.PerformSpatialQuery(this.TargetLayer.FeatureClass, this.SpatialFilter);
this.ResultCursor = featureCursor as ICursor;
}
if (this.dataGridView1 != null && this.ResultCursor != null)
{
this.FillDataGrid(this.dataGridView1);
}
}
public IFeatureCursor PerformSpatialQuery(IFeatureClass featureClass, ISpatialFilter filter)
{
IFeatureCursor featureCursor = featureClass.Search(filter, false);
return featureCursor;
}
private void FillDataGrid(DataGridView gridView)
{
if (gridView == null || this.TargetLayer == null || this.ResultCursor == null)
{
return;
}
IFeatureClass curFeatureClass = this.TargetLayer.FeatureClass;
this.dataGridView1.Columns.Clear();
IFields fields = ResultCursor.Fields;
for (int i = 0; i < fields.FieldCount; i++)
{
DataGridViewTextBoxColumn column = new DataGridViewTextBoxColumn();
column.HeaderText = fields.get_Field(i).Name;
this.dataGridView1.Columns.Add(column);
}
IRow row = ResultCursor.NextRow();
while (row != null)
{
object[] values = new object[row.Fields.FieldCount];
for (int i = 0; i < row.Fields.FieldCount; i++)
{
values[i] = row.Value[i];
}
this.dataGridView1.Rows.Add(values);
row = ResultCursor.NextRow();
}
}
}
}
（4）结果
加载地图
打开空间查询窗口
在道路图层中查询地震图层与州图层相交的要素
