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最近需要做一个自动刷新数据的功能。一般来说，自动刷新数据可以采用System.Windows.Forms.Timer来实现，不过我这次尝试着使用控制线程的方式实现自动刷新。

自动刷新效果如下图：

这个Demo程序，点击“查询”按钮可以立即手动刷新，勾选“开启自动刷新”复选框后，可以决定是否自动刷新，“暂离”和“回归”按钮，用于模拟窗体失去焦点的情况，点击“暂离”后，如果当前开启了自动刷新，则暂停自动刷新，点击“回归”按钮后，如果当前开启了自动刷新，则启用自动刷新。

程序中的控件名称如下：

这个Demo使用线程（Thread）每隔1秒都会随机生成DataGridView的数据源，并通过信号对线程进行控制。

程序代码如下：

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

namespace DataRefresher
{
    public partial class FormMain : Form
    {
        //刷新线程
        Thread thrRefresher;

        /// <summary>
        /// 用于控制线程的暂停和继续
        /// </summary>
        AutoResetEvent areRefresher = new AutoResetEvent(false);
        /// <summary>
        /// 控制标志：暂停线程
        /// </summary>
        bool bSign = true;
        /// <summary>
        /// 控制标志：中止线程
        /// </summary>
        bool bSignAlive = true;

        public FormMain()
        {
            InitializeComponent();
        }

        private void FormMain_Load(object sender, EventArgs e)
        {
            thrRefresher = new Thread(new ThreadStart(KeepOnRefreshData));
            chkAutoRefresh.Checked = true;
        }

        private void btnRefresh_Click(object sender, EventArgs e)
        {
            dgvData.DataSource = GetNewData();
        }

        private void chkAutoRefresh_CheckedChanged(object sender, EventArgs e)
        {
            //用于线程刷新模式的启动和暂停
            if (chkAutoRefresh.Checked)
            {
                bSign = true;

                //第一次勾选时启动进程
                if (thrRefresher.ThreadState == ThreadState.Unstarted)
                {
                    thrRefresher.Start();
                    areRefresher.Set();
                }

                areRefresher.Set();
            }
            else
            {
                bSign = false;
            }
        }
        
        //用于线程调用：不断刷新dgv
        private void KeepOnRefreshData()
        {
            while (true)
            {
                //如果外部窗体关闭，则从内部终止线程
                if (!bSignAlive)
                {
                    break;
                }

                RefreshData(dgvData, GetNewData());

                //执行一次后暂停一个信息获取周期的时间
                for (int i = 0; i < 10; i++)
                {
                    if (bSignAlive)
                    {
                        Thread.Sleep(100);
                    }
                    else
                    {
                        break;
                    }
                }

                //如果外部窗体关闭，则从内部终止线程
                if (!bSignAlive)
                {
                    break;
                }

                //如果接收到暂停标志，则暂停线程
                if (!bSign)
                {
                    areRefresher.WaitOne();
                }
            }
        }

        //给一个DataGridView赋值
        private delegate void RefreshDataDelegate(DataGridView dgv, DataTable dt);
        private void RefreshData(DataGridView dgv, DataTable dt)
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new RefreshDataDelegate(this.RefreshData), dgv, dt);
            }
            else
            {
                dgv.DataSource = dt;
            }
        }

        private DataTable GetNewData()
        {
            DataTable dt = new DataTable();

            dt.Columns.Add("序号");
            dt.Columns.Add("名称");
            dt.Columns.Add("力量");
            dt.Columns.Add("敏捷");
            dt.Columns.Add("智力");

            Random random = new Random(DateTime.Now.Millisecond);

            dt.Rows.Add("1", "秃驴",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("2", "独眼龙",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("3", "三脚猫",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("4", "绿帽王八",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("5", "四眼田鸡",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("6", "地头蛇",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("7", "单身狗",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("8", "替罪羊",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));
            dt.Rows.Add("9", "黄牛",
                random.Next(50, 100), random.Next(50, 100), random.Next(50, 100));

            return dt;
        }

        private void btnLeave_Click(object sender, EventArgs e)
        {
            if (chkAutoRefresh.Checked)
            {
                bSign = false;
            }
        }

        private void btnReturn_Click(object sender, EventArgs e)
        {
            if (chkAutoRefresh.Checked)
            {
                bSign = true;
                areRefresher.Set();
            }
        }

        private void FormMain_FormClosing(object sender, FormClosingEventArgs e)
        {
            bSignAlive = false;
            areRefresher.Set();
            thrRefresher.Join();
        }
    }
}

附：demo下载地址在 http://pan.baidu.com/s/1pJJ4vd5

END