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

namespace www.csframework.com
{
   public partial class Form1 : Form
   {
      public Form1()
      {
         InitializeComponent();
      }
      
      private void btnOpenDialog_Click(object sender, EventArgs e)
      {
         //调用对话框的ExecuteFind静态方法
         //打开一个对话框并传入参数。
         Form2.ExecuteFind(this, this.richTextBox1);
      }
   }
}

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

namespace www.csframework.com
{
   
   public partial class Form2 : Form
   {
      public Form2()
      {
         InitializeComponent();
      }
      
      //由外部传进来的对象.(*指针)
      private RichTextBox _RichTextBox = null;
      public RichTextBox RichTextBox { get { return _RichTextBox; } set { _RichTextBox = value; } }
      
      //当前窗体实例
      private static Form2 _Instance = null;
      public static void ExecuteFind(Form owner, RichTextBox richTextBox)
      {
         //引用设计模式的单件模式。永远只创建一个窗体。
         if (_Instance == null) _Instance = new Form2();
         
         _Instance.RichTextBox = richTextBox; //保存由外部传入的变量
         
         if (_Instance.Visible) //如果对话框实例已经打开，设置窗体焦点
         _Instance.Activate();
         else
         _Instance.Show(owner); //第一次打开，显示窗体。owner参数为
         //owner参数表示将拥有此窗体的顶级窗口的对象。
      }
      
      private void btnFind_Click(object sender, EventArgs e)
      {
         string s = textBox1.Text;
         
         //调用由外部传进来的对象的方法。
         int pos = _RichTextBox.Text.IndexOf(s);
         if (pos > 0)
         {
            RichTextBoxTool.FindFirst(this._RichTextBox, s);
         }
      }
      
      private void Form2_FormClosed(object sender, FormClosedEventArgs e)
      {
         _Instance = null; //当关闭窗体的时候，记得将变量设为null
      }
      
   }
}