timer控件，简单通讯

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

namespace 简单通讯
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

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

namespace 简单通讯
{
    class liaotian
    {
        public string fa { get; set; }
        public string shou { get; set; }
        public string neirong { get; set; }
        public DateTime shijian { get; set; }
        public bool zhuangtai { get; set; }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

namespace 简单通讯
{
    class liaotianData
    {
        SqlConnection conn = null;
        SqlCommand cmd = null;
        public liaotianData()
        {
            conn = new SqlConnection("server=.;database=Data0425;user=sa;pwd=123;");
            cmd = conn.CreateCommand();
        }

        public void Insert(liaotian lt)
        {
            cmd.CommandText = "insert into liaotian values(@fa,@shou,@neirong,@shijian,@zhuangtai)";
            cmd.Parameters.Clear();
            cmd.Parameters.Add("@fa", lt.fa);
            cmd.Parameters.Add("@shou", lt.shou);
            cmd.Parameters.Add("@neirong", lt.neirong);
            cmd.Parameters.Add("@shijian", lt.shijian);
            cmd.Parameters.Add("@zhuangtai", lt.zhuangtai);

            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        
        }

        public List<liaotian> Select(string shouID)
        {
            List<liaotian> list = null;
            cmd.CommandText = "select *from liaotian where shou = @shou";
            cmd.Parameters.Clear();
            cmd.Parameters.Add("@shou",shouID);

            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.HasRows)
            {
                list = new List<liaotian>();
                while (dr.Read())
                {
                    liaotian lt = new liaotian();
                    lt.fa = dr[0].ToString();
                    lt.shou = dr[1].ToString();
                    lt.neirong = dr[2].ToString();
                    lt.shijian = Convert.ToDateTime(dr[3]);
                    lt.zhuangtai = Convert.ToBoolean(dr[4]);

                    list.Add(lt);
                }
            }
            conn.Close();

            return list;
        }

        public void Delete(string neirong)
        {
            cmd.CommandText = "delete from liaotian where neirong = @neirong";
            cmd.Parameters.Clear();
            cmd.Parameters.Add("@neirong",neirong);
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }

        public liaotian Select2(string shouID)
        {
            liaotian list = null;
            cmd.CommandText = "select *from liaotian where shou = @shou";
            cmd.Parameters.Clear();
            cmd.Parameters.Add("@shou", shouID);

            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.HasRows)
            {
                list = new liaotian();
                while (dr.Read())
                {
                    list.fa = dr[0].ToString();
                    list.shou = dr[1].ToString();
                    list.neirong = dr[2].ToString();
                    list.shijian = Convert.ToDateTime(dr[3]);
                    list.zhuangtai = Convert.ToBoolean(dr[4]);
                }
            }
            conn.Close();

            return list;
        }

    }
}

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 简单通讯
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }



        private void timer1_Tick(object sender, EventArgs e)
        {
           
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2();
            f2.Show();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (!String.IsNullOrEmpty(textBox1.Text)) //如果发送的内容不是空，就可以发送
            {
                liaotian lll = new liaotian(); //新建一个聊天对象

                lll.fa = label1.Text; //谁发的信息
                lll.shou = "超人"; //发给谁
                lll.neirong = textBox1.Text; //发送内容
                lll.shijian = DateTime.Now; //发送时间
                lll.zhuangtai = true;

                new liaotianData().Insert(lll);

                richTextBox1.Text += lll.shijian+"  "+ lll.fa+ "对"+lll.shou+"说：\r"+lll.neirong;
                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.Windows.Forms;

namespace 简单通讯
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        //List<liaotian> ltxx = new List<liaotian>();
        liaotian zhong = null;

        private void timer1_Tick(object sender, EventArgs e)
        {
            zhong = new liaotianData().Select2(label1.Text); //查询出需要超人收的信息，查一条

            if (zhong != null)//如果查出来了，那么就需要显示
            {
                //将查出来的信息显示出来
                richTextBox1.Text += zhong.shijian + "  " + zhong.fa + "对" + zhong.shou + "说:\r" + zhong.neirong + "\r\r";
                //显示完毕后，在数据库删掉这条信息，防止重复查询显示
                new liaotianData().Delete(zhong.neirong);
            }
        }

        private void Form2_Load(object sender, EventArgs e)
        {

        }





    }
}

一个重要属性Interval，这个值设定每个多长时间执行一次动作，单位是毫秒，还有一个重要事件是Timer，双击Timer控件即可自动产生这个事件的框架，在这个框架里面写入每隔Interval毫秒就要执行的代码动作。
例如：
1.放一个Timer控件在窗体上
2.设置Timer控件的Interval属性为60000（表示60000毫秒，即一分钟）
3.双击Timer控件，在光标处写代码：msgbox("hello")
这样，每隔一分钟就弹出一个消息框，显示hello