ExcelHelp （Excel帮助类）

  public class ExcelHelp
    {
        public static string fileName = @"本地路径 ";
        private static OleDbConnection connection;
        public static OleDbConnection Connection
        {
            get
            {
                string connectionString = "";
                string fileType = System.IO.Path.GetExtension(fileName);
                if (string.IsNullOrEmpty(fileType)) return null;
                if (fileType == ".xls")
                {
                    connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + fileName + ";" + ";Extended Properties=\"Excel 8.0;HDR=YES;IMEX=2\"";
                }
                else
                {
                    connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + fileName + ";" + ";Extended Properties=\"Excel 12.0;HDR=YES;IMEX=2\"";
                }
                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;
            }
        }

        /// <summary>
        /// 执行无参数的SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <returns>返回受SQL语句影响的行数</returns>
        public static int ExecuteCommand(string sql)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            int result = cmd.ExecuteNonQuery();
            connection.Close();
            return result;
        }

        /// <summary>
        /// 执行有参数的SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="values">参数集合</param>
        /// <returns>返回受SQL语句影响的行数</returns>
        public static int ExecuteCommand(string sql, params OleDbParameter[] values)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            int result = cmd.ExecuteNonQuery();
            connection.Close();
            return result;
        }

        /// <summary>
        /// 返回单个值无参数的SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <returns>返回受SQL语句查询的行数</returns>
        public static int GetScalar(string sql)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            connection.Close();
            return result;
        }

        /// <summary>
        /// 返回单个值有参数的SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="parameters">参数集合</param>
        /// <returns>返回受SQL语句查询的行数</returns>
        public static int GetScalar(string sql, params OleDbParameter[] parameters)
        {
            OleDbCommand cmd = new OleDbCommand(sql, Connection);
            cmd.Parameters.AddRange(parameters);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            connection.Close();
            return result;
        }

        /// <summary>
        /// 执行查询无参数SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <returns>返回数据集</returns>
        public static DataSet GetReader(string sql)
        {
            OleDbDataAdapter da = new OleDbDataAdapter(sql, Connection);
            DataSet ds = new DataSet();
            da.Fill(ds, "UserInfo");
            connection.Close();
            return ds;
        }
        /// <summary>
        /// 执行查询有参数SQL语句
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="parameters">参数集合</param>
        /// <returns>返回数据集</returns>
        public static DataSet GetReader(string sql, params OleDbParameter[] parameters)
        {
            OleDbDataAdapter da = new OleDbDataAdapter(sql, Connection);
            da.SelectCommand.Parameters.AddRange(parameters);
            DataSet ds = new DataSet();
            da.Fill(ds);
            connection.Close();
            return ds;
        }      
       
    }