DataTable dt = dataGridView1.DataSource as DataTable;//把DataGridView绑定的数据源转换成DataTable
            foreach (DataRow row in dt.Rows)
            {
                //根据行的状态决定对数据库接行什么操作
                switch (row.RowState)
                {
                    case DataRowState .Added:
                        //把这一行添加回数据库
                        break;
                    case DataRowState.Deleted:
                        //把数据库里的这一行删除
                        break;
                    case DataRowState.Modified:
                        //更新数据库里的该条记录
                        break;
                }
            }

------解决方案--------------------
以下是我自己使用的一个 DBObject.cs类使用方法很简单．使用了ＯｌｅＤｂ数据库接口，
在初始化的时候，
DBObject db=new DBObject(你的数据库连接字符串);
string sql="select * from A where A1=1";
DataTable dt=db.GetTable(sql);
接下来对dt进行操作
dt.rows[0][1]="1" 设置第１行的第２列内容为１．．．
等等．．．

最后，要保存到数据库的时候，调用
db.UpdateDB(sql,dt);即可

C# code
using System;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Configuration;
using System.Web;

/// <summary>
/// Summary description for DBObject
/// </summary>
namespace Ben3.Core
{
    public class DBObject
    {
        private string connString;
        private SqlConnection conn;
        private SqlCommand cmd;
        private SqlCommandBuilder cb;
        private DataSet ds;
        private SqlDataAdapter da;
        private SqlDataReader dr;

        public DBObject(string connectionString)
        {
            if (connectionString.IndexOf(";") >= 0)
                connString = connectionString;
            else
            {
                ConnectionStringSettings settings = ConfigurationManager.ConnectionStrings[connectionString];
                connString = (settings.ConnectionString);
            }
        }
        public DBObject()
        {
            ConnectionStringSettings settings = ConfigurationManager.ConnectionStrings["dbConnectionString"];
            connString = (settings.ConnectionString);
        }
        public int RunSql(string sqlString)
        {
            using (conn = new SqlConnection(connString))
            {
                conn.Open();
                cmd = new SqlCommand(sqlString, conn);
                return cmd.ExecuteNonQuery();
            }
        }
        public object RunSql2(string sqlString)
        {
            using (conn = new SqlConnection(connString))
            {
                conn.Open();
                cmd = new SqlCommand(sqlString, conn);
                try { return cmd.ExecuteScalar(); }
                catch { return (object)0; }
            }
        }
        public string RunSql(string sqlString, int columnID)
        {
            using (conn = new SqlConnection(connString))
            {
                conn.Open();
                cmd = new SqlCommand(sqlString, conn);
                dr = cmd.ExecuteReader();
                if (!dr.Read())
                    return "#";
                else
                    return dr[columnID].ToString();
            }
        }

        public string RunSql(string sqlString, string columnName)
        {
            using (conn = new SqlConnection(connString))
            {
                conn.Open();
                cmd = new SqlCommand(sqlString, conn);
                dr = cmd.ExecuteReader();
                if (!dr.Read())
                    return "#";
                else
                    return dr[colum