C# DataGridView分页显示

//导入命名空间部分省略

DBClass.DBExecute dbexecute = new DBExecute();        

string connectionString = @"Data Source=ServerName;Database=DatabaseName;integrated security=true";

        #region 初始化分页显示的参数    
        static int rowsall = 0;//总行数      
        static int pageall = 0;//总页数
        static int page = 0;//第几页
        static int count = 20;//返回20行
        static int start = 0;//从第start行开始返回
        #endregion

        #region 建立数据库链接
        /// <summary>
        /// 建立数据库连接
        /// </summary>
        /// <returns>返回SqlConnection对象</returns>
        public SqlConnection getcon()
        {
            SqlConnection myCon = new SqlConnection(connectionString);           
            return myCon;
        }

        #region 设置DataGridView分页显示的参数，和初次绑定
        /// <summary>
        /// 设置DataGridView分页显示的参数，和初次绑定
        /// </summary>
        /// <param name="sqlstr">设置查询的sql语句</param>
        /// <param name="table">设置返回绑定的DataSet中的表的名称</param>
        /// <param name="dgv">要绑定的DataGridView</param>         
        public void upPage(string sqlstr,string table,DataGridView dgv)
        {
            rowsall = dbexecute.getds(sqlstr, table).Tables[table].Rows.Count;//总行数
            if (rowsall == 0)
            {
                //如果没有数据则将第一页、上一页、下一页、最后一页设置为不可用；并设置其他参数
                toolStripButton2.Enabled = false;
                toolStripButton3.Enabled = false;
                toolStripButton4.Enabled = false;
                toolStripButton5.Enabled = false;
                page = 0;
                pageall = 0;
                rowsall = 0;
                dgv.DataSource = null;
                tslRowsall.Text = rowsall.ToString();
                tslPageAll.Text = pageall.ToString();
                tslPage.Text = page.ToString();
                return;
            }
            if (rowsall > 0)//判断是否有内容
            {
                page = 1;//如果有内容，设置为第一页
                start = 0;
            }           
            int yushu = rowsall % count;//是否存在余行
            if (yushu == 0)//不存在余行时设置总页数
            {
                if (rowsall > 0 && rowsall <= count)
                {
                    pageall = 1;
                }
                else
                {
                    pageall = rowsall / count;
                }
            }
            else//存在余行时设置总页数
            {
                pageall = rowsall / count + 1;
            }
            {//设置显示数据，
                tslRowsall.Text = rowsall.ToString();
                tslPageAll.Text = pageall.ToString();
                tslPage.Text = page.ToString();
                if (pageall > 0)
                { //设置跳转到第几页
                    
                     tscbPage.Items.Clear();
                    for (int i = 1; i <= pageall; i++)
                        tscbPage.Items.Add(i);
                }
            }
            selectsql = sqlstr; //设置sql语句
            dgv.DataSource = gettb(selectsql ,start,count,"table")‘;//绑定DataGridView

        }
        #endregion

        #region
        /// <summary>
        /// 分页返回DataTable
        /// </summary>
        /// <param name="sql">查询的sql语句</param>
        /// <param name="i">从第i行开始返回</param>
        /// <param name="j">共返回j行记录</param>
        /// <param name="tablename">返回DataSet中的表明</param>
        /// <returns>返回DataTable</returns>
        public DataTable gettb(string sql, int start, int count, string tablename)
        {
            SqlConnection con = this.getcon();
            DataSet myds = new DataSet();
            SqlDataAdapter sda = new SqlDataAdapter(sql, con);

            sda.Fill(myds, start, count, tablename);
            return myds.Tables[tablename];
        }
        #endregion

        /// 第一页
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            if (pageall > 1)
            {
                start = 0;
                page = 1;
                tslPage.Text = page.ToString();
                this.dataGridView1.DataSource = gettb(selectsql ,start,count,"table")‘;//绑定DataGridView
            }
        }

        // 上一页
        private void toolStripButton3_Click(object sender, EventArgs e)
        {
            if (page >1)
            {               
                page--;
                start -= 20;               
                tslPage.Text = page.ToString();
                 this.dataGridView1.DataSource = gettb(selectsql ,start,count,"table")‘; //绑定DataGridView
            }      

        }

        /// 下一页
        private void toolStripButton4_Click(object sender, EventArgs e)
        {
            if (page < pageall)
            {               
                page++;
                start += 20;               
                tslPage.Text = page.ToString();
                this.dataGridView1.DataSource = gettb(selectsql ,start,count,"table")‘;//绑定DataGridView
            }      
           
        }

         //最后一页
        private void toolStripButton5_Click(object sender, EventArgs e)
        {
            if (pageall > 0)
            {
                start = (pageall - 1) * count;
                page = pageall;
                tslPage.Text = page.ToString();
                 this.dataGridView1.DataSource = gettb(selectsql ,start,count,"table")‘;//绑定DataGridView
            }
        }

上边红色部分获取总行数是调用的数据操作层里的getds方法返回一个数据集，类和方法如下：

class DBExecute
    {
        string G_str_connectionString = @"Data Source=70AB360C9ABA49E/SQLEXPRESS;Database=db_CRM;integrated security=true";//这里设置成你自己的连接
        public DBExecute(){}
        public DBExecute(string M_str_connectionString)
        {
            G_str_connectionString = M_str_connectionString;
        }
        #region 建立数据库链接
        /// <summary>
        /// 建立数据库连接
        /// </summary>
        /// <returns>返回SqlConnection对象</returns>
        public SqlConnection getcon()
        {
            string M_str_sqlcon = G_str_connectionString;
            SqlConnection myCon = new SqlConnection(M_str_sqlcon);           
            return myCon;
        }
        #endregion
#region 查询数据库返回一个DataSet对象
        /// <summary>
        /// 查询数据库返回一个DataSet对象
        /// </summary>
        /// <param name="M_str_sqlstr">SQL语句</param>
        /// <param name="M_str_table">表名</param>
        /// <returns>返回DataSet对象</returns>
        public DataSet getds(string M_str_sqlstr, string M_str_table)
        {
            DataSet myds = new DataSet();
            SqlConnection sqlcon = this.getcon();
            SqlDataAdapter sqlda = new SqlDataAdapter(M_str_sqlstr, sqlcon);
            sqlda.Fill(myds, M_str_table);          
            return myds;
        }
        #endregion
}