C#操作Excel

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Interop.Excel;
using System.Reflection;

namespace ListToExcel
{
    class Program
    {
        static List<objtype> objs = new List<objtype>();
        static void Main(string[] args)
        {
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            objs.Add(new objtype() { name = "allen", val = "aaa" });
            ExportDataToExcel("", "", @"c:\a.xls", "a");
        }
        /// <summary> 
        /// 直接导出数据到excel 
        /// </summary> 
        /// <param name="connectionString">连接字符串</param> 
        /// <param name="sql">查询语句</param> 
        /// <param name="fileName">文件名</param> 
        /// <param name="sheetName">表名</param> 
        static void ExportDataToExcel(string connectionString, string sql, string fileName, string sheetName)
        {
            Application app = new Application();
            Workbook wb = app.Workbooks.Add(Missing.Value);
            Worksheet ws = wb.Worksheets.Add(Missing.Value, Missing.Value, Missing.Value, Missing.Value) as Worksheet;
            ws.Name = sheetName;
            try
            {
                int n = 0;

                for (int i = 1; i < objs.Count; i++)
                {
                      var excelRange = (Range)ws.Cells[i, 1]; 
                   excelRange.Value2 = objs[i].val;//Value2? 
                   excelRange = null; 
                }
            }
            catch (Exception ex)
            {
                string str = ex.Message;
            }
            finally
            {
                wb.Saved = true;
                wb.SaveCopyAs(fileName);//保存 
                app.Quit();//关闭进程 
            }
        }
    }
    class objtype
    {
        public string name { get; set; }
        public string val { get; set; }
    }
}