事件一二

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;

namespace DelegateTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public delegate void DrawGeoObjectDelegate(GeoFileds geoFileds, object obj);
        public event DrawGeoObjectDelegate DrawGeoObjectEvent;
        test test = null;
        private void Form1_Load(object sender, EventArgs e)
        {
             test = new test(this);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (DrawGeoObjectEvent!=null)
            {
                GeoFileds geo = new GeoFileds();
                geo.LayerName = "nihao";
                DrawGeoObjectEvent(geo,sender);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            test.Remove();
            if (DrawGeoObjectEvent == null)
            {
                MessageBox.Show("委托清空");
            }
           
        }
    }
    public struct GeoFileds
    {
        public string LayerName;
        public string ClassifyName;
        public string GeoName;
        public int GeoCode;
        public string BZ;
        public string IconPath;
        public Color lineColor;
        public double lineWidth;
        public Color fillColor;
        public Dictionary<string, string> ExtField;
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DelegateTest
{
    class test
    {
        Form1 frm = null;
        public test(Form1 frm1)
        {
            frm = frm1;
            frm.DrawGeoObjectEvent += new Form1.DrawGeoObjectDelegate(frm_DrawGeoObjectEvent);
        }

        void frm_DrawGeoObjectEvent(GeoFileds geoFileds, object obj)
        {
            MessageBox.Show("图层："+geoFileds.LayerName);

        }
        public void Remove()
        {
            frm.DrawGeoObjectEvent -= new Form1.DrawGeoObjectDelegate(frm_DrawGeoObjectEvent);
        }
    }
}