?using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
//增加命名空間
using System.Data.SqlClient;

/// <summary>
/// DB 的摘要說明
/// </summary>
public class DB
{
    SqlConnection con = null;
    SqlCommand cmd = new SqlCommand();

    //DB構造函數
	public DB()
	{
        con = new SqlConnection("server=.\\SQLEXPRESS;database=vote;uid=sa;pwd=sa;");
	}

    //打開數據庫連接
    public SqlConnection getCon()
    {
        if(con.State==ConnectionState.Closed)
            con.Open();
        return con;
    }

    //關閉數據庫連接
    public void clear()
    {
        if(con.State==ConnectionState.Open)
            con.Close();
    }

    //取出標題
    public string executeGetReturn(string sqlcon)
    {
        cmd.Connection = getCon();
        cmd.CommandText = sqlcon;

        String result = Convert.ToString(cmd.ExecuteScalar());
        clear();
        return result;
    }

    //取出標題項目
    public SqlDataReader getSdr(string sqlcon)
    { 
        cmd.Connection=getCon();
        cmd.CommandText = sqlcon;

        SqlDataReader sdr = cmd.ExecuteReader();
        return sdr;
    }

    //將投票者的IP和投票時間寫入數據庫
    public int executeNonQuery(string sqlcon)
    {
        cmd.Connection = getCon();
        cmd.CommandText = sqlcon;
        int i=cmd.ExecuteNonQuery();
        clear();
        return i;
    }

    //設置投票的事物機制
    public bool executeTransaction(string[] sqlcon)
    {
        bool flag = false;
        con = getCon();
        cmd.Connection = con;

        SqlTransaction voteTransaction=con.BeginTransaction();
        try
        {
            foreach (string sql in sqlcon)
            {
                cmd.Transaction = voteTransaction;
                cmd.CommandText = sql;
                cmd.ExecuteNonQuery();
            }
            voteTransaction.Commit();
            flag = true;
        }

        catch (Exception e)
        {
            voteTransaction.Rollback();
            flag = false;
        }
        finally 
        {
            clear();
        }
        return flag;
    }

}