C# 委托例子

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Form2 fm2 = new Form2();
            fm2.msgSender = this.Receiver; //[3]将委托对象和方法关联
            fm2.Show();

            Form3 fm3 = new Form3();
            fm3.msgSender = this.Receiver; //[3]将委托对象和方法关联
            fm3.Show();
        }

        //[2]根据委托定义方法完成数据传递
        public void Receiver(string info)
        {
            this.label2.Text = info;
        }
   
    }
        //[1]声明委托，一般定义在外面
        public delegate void ShowInfo(string param);
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }
        //创建委托对象
        public ShowInfo msgSender;


        //通过委托传递数据
        private void button1_Click(object sender, EventArgs e)
        {
            msgSender(this.textBox1.Text);
        }
 
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }

        //创建委托对象[从到主]
        public ShowInfo msgSender;

        private void button1_Click(object sender, EventArgs e)
        {
            msgSender(this.textBox1.Text);
        }
         
    }
}