ArcEngine C# GIS开发入门作业 （四）Ex05——空间数据库查询选中要素高亮，并计算

题目：

实现效果

注意事项先不重复了，前面几篇文章都有，直接上代码，这几天在实习要顺便写个实习的文章，这个作业就先还来不及行行注释了，为了保持作业的连续性，先把作业发完，后面再注释：

form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.ADF;
using ESRI.ArcGIS.SystemUI;
using ESRI.ArcGIS;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;

namespace Ex05
{
    public partial class Form1 : Form
    {
        #region class private members
        private IMapControl3 m_mapControl = null;
        private string m_mapDocumentName = string.Empty;
        #endregion

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //get the MapControl
            m_mapControl = (IMapControl3)axMapControl1.Object;

            //disable the Save menu (since there is no document yet)
        }

        private void axMapControl1_OnMouseDown(object sender, ESRI.ArcGIS.Controls.IMapControlEvents2_OnMouseDownEvent e)
        {
            IPoint pPoint = new PointClass();
            ITopologicalOperator pTopologicalOperator = pPoint as ITopologicalOperator;
            pPoint.PutCoords(e.mapX, e.mapY);
            IGeometry pGeometry = pTopologicalOperator.Buffer(0);
            axMapControl1.Map.SelectByShape(pGeometry, null, false);
            axMapControl1.Refresh(esriViewDrawPhase.esriViewGeoSelection, null, null);
             
        }

        private void axMapControl1_OnMapReplaced(object sender, IMapControlEvents2_OnMapReplacedEvent e)
        {
            //get the current document name from the MapControl
            m_mapDocumentName = m_mapControl.DocumentFilename;

        }

        private void QueryFilter_Click(object sender, EventArgs e)
        {
            if (axMapControl1.Map.LayerCount != 0)
            {
                IFeatureLayer pGeoLayer = this.axMapControl1.get_Layer(2) as IFeatureLayer;
                ITable pTable = pGeoLayer.FeatureClass as ITable;
                IFeatureCursor pCursor;
                IQueryFilter pQueryFilter = new QueryFilter();
                pQueryFilter.WhereClause = "LANDLOCKED = \'Y\'";
                pCursor = (IFeatureCursor)pTable.Search(pQueryFilter, true);
                IFeature pFea = pCursor.NextFeature();
                double area = 0;
                IArea pAea = pFea.Shape as IArea;
                if (pFea != null)
                {
                    if (pFea.Shape.GeometryType == esriGeometryType.esriGeometryPolygon)
                    {
                        area = area + pAea.Area;
                        pFea = pCursor.NextFeature();
                    }
                }
                int i = 1;
                while (pFea != null)
                {
                    i++;
                    if (pFea.Shape.GeometryType == esriGeometryType.esriGeometryPolygon)
                    {
                        area = area + pAea.Area;
                        pFea = pCursor.NextFeature();
                    }
                }
                MessageBox.Show(i + " countries with LANDLOCKED = Y \n " + "The sum of acreage:" + area + " Square Meter");
            }
        }

        private void SpatialFliter_Click(object sender, EventArgs e)
        {
            ISelection pSelection = axMapControl1.Map.FeatureSelection;
            IEnumFeatureSetup pEnumFeatureSetup = pSelection as IEnumFeatureSetup;
            pEnumFeatureSetup.AllFields = true;
            IEnumFeature pEnumFeature = pSelection as IEnumFeature;
            IFeature pFeature = pEnumFeature.Next();
            if (pFeature != null)
            {

                IFeatureLayer pFL = (IFeatureLayer)axMapControl1.get_Layer(0);
                IFeatureClass pFC = pFL.FeatureClass;
                ISpatialFilter pSF = new SpatialFilterClass();
                pSF.WhereClause = "Population>2000000";
                pSF.Geometry = pFeature.Shape;
                pSF.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains;
                IFeatureCursor pCursor;
                pCursor = pFC.Search(pSF, true);
                MessageBox.Show(pFC.FeatureCount(pSF) + " cities with population > 2000000");

            }
            else MessageBox.Show("未选中Country");
        }

        private void SelectCities_Click(object sender, EventArgs e)
        {
            ISelection pSelection = axMapControl1.Map.FeatureSelection;
            IEnumFeatureSetup pEnumFeatureSetup = pSelection as IEnumFeatureSetup;
            pEnumFeatureSetup.AllFields = true;
            IEnumFeature pEnumFeature = pSelection as IEnumFeature;
            IFeature pFeature = pEnumFeature.Next();
            if (pFeature != null)
            {

                IFeatureLayer pFL = (IFeatureLayer)axMapControl1.get_Layer(0);
                IFeatureClass pFC = pFL.FeatureClass;
                ISpatialFilter pSF = new SpatialFilterClass();
                pSF.WhereClause = "Population>2000000";
                pSF.Geometry = pFeature.Shape;
                pSF.SpatialRel = esriSpatialRelEnum.esriSpatialRelContains;
                IFeatureCursor pCursor;
                pCursor = pFC.Search(pSF, true);
                IFeatureSelection pFS = pFL as IFeatureSelection;
                pFS.SelectFeatures(pSF, esriSelectionResultEnum.esriSelectionResultAdd, false);
                axMapControl1.ActiveView.Refresh();

            }
            else MessageBox.Show("未选中Country");
        }


    }
}

program.cs

using System;
using System.Collections.Generic;
using System.Windows.Forms;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS;

namespace Ex05
{
    static class Program
    {
        private static LicenseInitializer m_AOLicenseInitializer = new 王晓佳_1609040125_Ex05.LicenseInitializer();
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            ESRI.ArcGIS.RuntimeManager.Bind(ESRI.ArcGIS.ProductCode.EngineOrDesktop);
            //ArcGIS的控件需要这行代码的绑定访问
            if (!RuntimeManager.Bind(ProductCode.Engine))
            {
                if (!RuntimeManager.Bind(ProductCode.Desktop))
                {
                    MessageBox.Show("Unable to bind to ArcGIS runtime. Application will be shut down.");
                    return;
                }
            }

            //ESRI License Initializer generated code.
            m_AOLicenseInitializer.InitializeApplication(new esriLicenseProductCode[] { esriLicenseProductCode.esriLicenseProductCodeEngine },
            new esriLicenseExtensionCode[] { });
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
            //ESRI License Initializer generated code.
            //Do not make any call to ArcObjects after ShutDownApplication()
            m_AOLicenseInitializer.ShutdownApplication();
        }
    }
}