获取数据库值,再在其值上做修改

开始想用SqlDataReader读取数据值再修改

            SqlDataReader rea = cmm.ExecuteReader();
            if (rea.Read())
            {
                rea["yuedu"] = (int)rea["yuedu"] + 1;

            }

结果报错,原因貌似SqlDataReader是只读的

后面用SqlDataAdapter解决了,

  int i = Convert.ToInt32(Request.QueryString["id"]);
       
        using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["sqlstr"].ConnectionString))
        {
            SqlCommand cmm = new SqlCommand("select * from new where ID='" + i + "'", con);
            SqlDataAdapter ada = new SqlDataAdapter();
            ada.SelectCommand = cmm;
            SqlCommandBuilder bui = new SqlCommandBuilder(ada);
            DataSet ds = new DataSet();
            ada.Fill(ds, "tb1");
            int num = Convert.ToInt32(ds.Tables["tb1"].Rows[0][5]);
            ds.Tables["tb1"].Rows[0][5] = (num + 1).ToString();
            ada.Update(ds, "tb1");

       PS:1.SqlDataAdapter必须选取主键才能更新

            2.不必开关执行sqlconnection.
        }

留住以后参考.