?using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.OleDb;

namespace DAL.Access
{
   public static class DBHelper
    {
         private static OleDbConnection connection;
        public static OleDbConnection Connection
        {
            get
            {
                string connectionString = "provider=Microsoft.Jet.OLEDB.4.0;data Source=" ;
                if (connection == null)
                {
                    connection = new OleDbConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Closed)
                {
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }
                return connection;
            }
        }

       public static int ExecuteCommand(params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = Connection;
            cmd.CommandText = "Pro_UpdateName";
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddRange(values);
            int result = cmd.ExecuteNonQuery();
            return result;
        }

        public static int ExecuteCommand(string safeSql)
        {
            OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
            int result = cmd.ExecuteNonQuery();
            return result;
        }

       public static int ExecuteCommand(string sql, params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            return cmd.ExecuteNonQuery();
        }

        public static int GetScalar(string safeSql)
        {
            OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }
        //public static T GetScalar <T> (string safeSql)
        //{
        //    using (SqlCommand cmd = new SqlCommand(safeSql, Connection))
        //    {
        //        T result = (T)cmd.ExecuteScalar();
        //        return result;
        //    }
        //}

        public static T ExecuteScalar<T>(string safeSql,params OleDbParameter[] pars)
        {
            using (OleDbCommand cmd = new OleDbCommand(safeSql, Connection))
            {
                //for (int i = 0; pars != null && i < pars.Length; i++)
                //{
                //    cmd.Parameters.Add((SqlParameter)((ICloneable)pars[i]).Clone());
                //}
                cmd.Parameters.AddRange(pars);
                T result = (T)cmd.ExecuteScalar();
                return result;
            }
        }

        public static T ExecuteScalar<T>(string safeSql)
        {
            return ExecuteScalar<T>(safeSql, null);
        }
       public static int GetScalar(params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = Connection;
            cmd.CommandText = "Pro_InsertName";
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddRange(values);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }

       public static int GetScalar(string sql, params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }

        public static OleDbDataReader GetReader(string safeSql)
        {
            OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
           OleDbDataReader reader = cmd.ExecuteReader();
            return reader;
        }

       public static OleDbDataReader GetReader(string sql, params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            OleDbDataReader reader = cmd.ExecuteReader();
            return reader;
        }

        public static DataTable GetDataSet(string safeSql)
        {
            DataSet ds = new DataSet();
            OleDbCommand cmd = new OleDbCommand(safeSql, Connection);
            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            da.Fill(ds);
            return ds.Tables[0];
        }

       public static DataTable GetDataSet(string sql, params OleDbParameter[] values)
        {
            DataSet ds = new DataSet();
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            da.Fill(ds);
            return ds.Tables[0];
        }

    }
}