using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.Common;

namespace OCXMLCreater.ExcelProvider
{
    public class ExcelHelper
    {

        //唯一需要解释的一点是这个连接字符串中，HDR=YES 表示此Excel表第一行用于显示字段名称（Header），如果没有字段名，则应 HDR=NO
        public static string connectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\WorkSpace\MyDocument\Samples2.xlsx;Extended Properties=""Excel 8.0;HDR=YES;""";

        /// <summary>
        /// 读取 Excel 返回 DataSet
        /// </summary>
        /// <param name="connectionString">Excel 连接字符串</param>
        /// <param name="commandString">查询语句, for example:"SELECT ID,userName,userAddress FROM [Sheet1$]" </param>
        /// <returns></returns>
        public static DataSet GetExcelDataSet(string connectionString, string commandString)
        {
            DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OleDb");

            DbDataAdapter adapter = factory.CreateDataAdapter();

            DbCommand selectCommand = factory.CreateCommand();
            selectCommand.CommandText = commandString;  //commandString例如:"SELECT ID,userName,userAddress FROM [Sheet1$]"

            DbConnection connection = factory.CreateConnection();
            connection.ConnectionString = connectionString;

            selectCommand.Connection = connection;
            adapter.SelectCommand = selectCommand;

            DataSet cities = new DataSet();
            adapter.Fill(cities);

            connection.Close();
            return cities;
        }
    }
}