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 WindowsFormsApplication1 
 { 
   public partial class Form1 : Form 
   { 
     public Form1() 
     { 
       InitializeComponent(); 
     } 
  
     private void Form1_Load(object sender, EventArgs e) 
     { 
  
     } 
     public void renovate() 
     { 
       //刷新的代码 
     } 
   } 
 } 
 

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 WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        private Form1 _MyForm1 = new Form1();

        public Form1 MyForm1
        {
            get { return _MyForm1; }
            set { _MyForm1 = value; }
        }

        
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //回调Form1的刷新事件
            _MyForm1.Invoke(new Action(_MyForm1.renovate));
            //更多的操作可以看看Invoke的详细资料，也可以看看多线程之间的通信资料
        }
    }
}