arcgis engine 实现在图上画一个点，让其随机移动的代码实现

以下是使用ArcGIS Engine实现在图上画一个点，并让其随机移动的代码实现：

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.Controls;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Display;

namespace RandomPointMove
{
    public partial class Form1 : Form
    {
        private IMapControl3 m_pMapControl;
        private IGraphicsContainer m_pGraphicsContainer;
        private IPoint m_pPoint;
        private Random m_pRandom;

        public Form1()
        {
            InitializeComponent();
            axMapControl1.OnMouseDown += new IMapControlEvents2_Ax_OnMouseDownEventHandler(axMapControl1_OnMouseDown);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            m_pMapControl = axMapControl1.Object as IMapControl3;
            m_pGraphicsContainer = m_pMapControl.Map as IGraphicsContainer;
            m_pRandom = new Random(DateTime.Now.Millisecond);
        }

        private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e)
        {
            if (e.button == 1)
            {
                IPoint pPoint = m_pMapControl.ToMapPoint(e.x, e.y);
                AddPointGraphic(pPoint);
            }
        }

        private void AddPointGraphic(IPoint pPoint)
        {
            m_pPoint = pPoint;
            IMarkerSymbol pMarkerSymbol = new SimpleMarkerSymbolClass();
            IRgbColor pColor = new RgbColorClass();
            pColor.Red = 255;
            pMarkerSymbol.Color = pColor;
            pMarkerSymbol.Size = 10;
            IElement pElement = new MarkerElementClass();
            pElement.Geometry = m_pPoint;
            pElement.Symbol = pMarkerSymbol;
            m_pGraphicsContainer.AddElement(pElement, 0);
            m_pMapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            double x = m_pPoint.X + m_pRandom.NextDouble() * 100 - 50;
            double y = m_pPoint.Y + m_pRandom.NextDouble() * 100 - 50;
            m_pPoint.PutCoords(x, y);
            IElement pElement = m_pGraphicsContainer.Element[0];
            pElement.Geometry = m_pPoint;
            m_pGraphicsContainer.UpdateElement(pElement);
            m_pMapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
        }
    }
}

这段代码中，我们首先在`IMapControlEvents2_OnMouseDownEvent`事件中添加了一个点的图形，然后在`timer1_Tick`事件中随机移动这个点的位置，通过`IGraphicsContainer`接口实现图形的添加、更新和刷新。