列車時刻查詢系統(北大青鳥大二寒假作業) 源代碼(四)

數據層,包括對數據庫的所有操作.重組DataTable等

using System;
using System.Data;
using System.Data.SqlClIEnt;
using System.ComponentModel;

namespace train
...{
    /**//// <summary>
    /// 數據層操作類
    /// </summary>
    public class DataBaSEOperate
    ...{
        private SqlConnection conn;
        private TrainConfiguration config;
        private string path;
        public DataBaSEOperate()
        ...{
            conn=new SqlConnection();
            config=new TrainConfiguration();
            path=Environment.CurrentDirectory+"\config\config.txt";
        }


        /**//// <summary>
        /// 打開數據庫連接
        /// </summary>
        /// <returns>返回bool值，true表示連接成功,false表示連接失敗</returns>
        public bool ConnectDataBase()
        ...{
            try
            ...{
                if(conn.State!=ConnectionState.Open)
                ...{
                    conn.ConnectionString=config.GetConfigFromFile(this.path);
                    conn.Open();
                    return true;
       &nbs
p;        }
                else
                ...{
                    return true;
                }
            }
            catch(SqlException e)
            ...{
                Console.WriteLine(e.Message);
                return false;
            }
        }


        /**//// <summary>
        /// 關閉數據庫連接
        /// </summary>
        /// <returns>返回bool值，true表示關閉成功,false表示關閉失敗</returns>
        public bool CloseDataBase()

  ...{
            try
            ...{
                if(conn.State!=ConnectionState.Closed)
                ...{
                    conn.Close();
                }
                return true;
                
            }
            catch(SqlException)
            ...{
                return false;
            }
        }

   /**//// <summary>
        /// 根據sql語句執行數據庫查詢
        /// </summary>
        /// <param name="querysql">要執行的sql語句</param>
        /// <returns>返回一個DataTable集合</returns>
        public DataTable search(string querysql)
        ...{
            if(conn.State!=ConnectionState.Open)
            ...{
                ConnectDataBase();
            }
            ConnectDataBase();
            SqlCommand cmd=new SqlCommand(querysql,conn);
            SqlDataReader dr=null;
            try
            ...{
                dr=cmd.ExecuteReader();
            }
            catch(SqlException e)
  ...{
                Console.WriteLine(e.Message);
                return null;
            }
            //根據DataReader重組一個DataTable
            DataTable table=new DataTable();
            int colum=dr.FIEldCount;
            table.BeginLoadData();
            for(int i=0;i<colum;i++)
            ...{
                table.Columns.Add(dr.GetName(i),dr.GetType());
            }
            object[] values=new object[colum];
            while(dr.Read())
            ...{
                DataRow row=table.NewRow();
                dr.GetValues(values);
                for(int i=0;i<values.Length;i++)

   ...{
                    row[i]=values[i];
                }
                table.Rows.Add(row);
            }
            table.EndLoadData();
            dr.Close();
            return table;
        }
    }
}