最近做了一個功能，將頁面查詢的表格資料匯出到excel表格中，利用NOPI的方法做匯出功能。

1.下載NOPI.dll並引用到專案中。

2.前端頁面的匯出方法：

 //匯出
    function btnExport() {
        var colArr = [];
        //這裡寫獲取頁面表格欄位的顯示名稱，並存到colArr數組裡面，為了方便在後臺迴圈渲染。

        if(colArr.length == 0){
            alert("請查詢要匯出的資料！");
            return;
       }
        
        //這裡是要傳到後臺查詢資料的查詢條件，根據自己所要傳的引數進行修改，ColNames這個傳上面獲取欄位顯示名稱的陣列
        
 
var searchdata = {
            AreaNO: $('#chooseBox').val(),
            StartTime: sDateResult,
            EndTime: sDateResult,
            ColNames: colArr
        };
        //QueryType可以自己定義，後臺會根據這個進行判斷匯出對應的頁面資料
        var postData = { QueryType: 1, FileName: "你想要匯出的檔名稱", QueryParms: JSON.stringify(searchdata) };
        $.post(
 
"/Export/ExcelExport", postData, function (data) {
            if (data) {
                location.href = '/Export/GetExcelFile?download=' + data; //根據後臺返回檔名稱進行下載
            }
        });
    }

3.後臺的對應的方法：

public class ExportController : Controller
    {
        /// <summary>
        /// 下載Excel檔案
        
 
/// </summary>
        /// <param name="download"></param>
        /// <returns></returns>
        public FileResult GetExcelFile(string download)
        {
            FileStream fs = (FileStream)Session[download];
            Session.Remove(download);
            return File(fs, "application/vnd.ms-excel", download);
        }

        /// <summary>
        /// 匯出Excel表格
        /// </summary>
        /// <param name="QueryType"></param>
        /// <param name="FileName"></param>
        /// <param name="QueryParms"></param>
        /// <returns></returns>
        public string ExcelExport(int queryType, string fileName, string queryParms)
        {
            QueryParmsObj o = new QueryParmsObj();
            QueryParmsObj request = (QueryParmsObj)JsonToObject(queryParms, o);
            System.IO.FileStream fs;
            fileName = fileName + "_匯出資料_" + DateTime.Now.ToString("yyyyMMddHHmmss");
            string download = string.Format(@"{0}.xlsx", fileName);
            try
            {
                //建立Excel檔案的物件
                IWorkbook workbook = new HSSFWorkbook();

                //根據不同的型別匯出不同的報表
                if (queryType == 1) 
                {
                    //這裡通過引數查詢獲取要匯出的資料
                    var otherController = DependencyResolver.Current.GetService<FinancialAnalysisController>();
                    var response = otherController.FinancialAnalysisMConerlistData(request.AreaNO,request.StartTime,request.EndTime,null,null,null,null);
                    JObject list = (JObject)JsonConvert.DeserializeObject(response);
                    GetRowsOfType1(workbook, list, fileName,request.ColNames);
                }
                else if (queryType == 2)
                {

                }


                string pathString = Request.ApplicationPath;
                var mappath = Server.MapPath(pathString);
                var domainPath = AppDomain.CurrentDomain.GetData("DataDirectory").ToString();

                if (!Directory.Exists(string.Format("{0}\\Report", domainPath)))
                {
                    Directory.CreateDirectory(string.Format("{0}\\Report", domainPath));
                }

                string filePath = String.Format(@"{0}\\Report\\{1}_{2}.xlsx", domainPath, fileName, DateTime.Now.ToString("yyyyMMddHHmmss"));

                // 寫入到客戶端
                fs = new FileStream(filePath, FileMode.OpenOrCreate);

                workbook.Write(fs);
                fs.Seek(0, SeekOrigin.Begin);
            }
            catch (Exception)
            {
                throw new Exception();
            }
            Session[download] = fs;
            return download;
        }

        /// <summary>
        /// 匯出格式和資料渲染
        /// </summary>
        /// <param name="workbook"></param>
        /// <param name="list"></param>
        /// <param name="name"></param>
        /// <param name="colNames"></param>
        /// <returns></returns>
        private IWorkbook GetRowsOfType1(IWorkbook workbook, JObject list, string name,List<string> colNames)
        {
            //新增一個sheet
            ISheet sheet1 = workbook.CreateSheet("Sheet1");
            int colSpan = colNames.Count-1;
            SetSheetTitle(workbook, sheet1, name,colSpan);

            IRow row2 = sheet1.CreateRow(2);
            for (var i = 0; i < colNames.Count; i++)
            {
                row2.CreateCell(i).SetCellValue(colNames[i]);
            }

            //將資料逐步寫入sheet1各個行
            var listData = list["data"];
            for (int i = 0; i < listData.ToList().Count; i++)
            {
                IRow rowtemp = sheet1.CreateRow(i + 3);
                var cellVal = "";
                for (int j = 0; j < listData[i].ToList().Count; j++)
                {
                    cellVal = listData[i].ToList()[j].First.ToString();
                    rowtemp.CreateCell(j).SetCellValue(cellVal);
                }
            }
            return workbook;
        }

        /// <summary>
        /// 設定匯出Excel標題
        /// </summary>
        /// <param name="workbook"></param>
        /// <param name="sheet1"></param>
        /// <param name="name"></param>
        private void SetSheetTitle(IWorkbook workbook, ISheet sheet1, string name,int colSpan)
        {
            //給sheet1新增第一行的頭部標題
            IRow row0 = sheet1.CreateRow(0);
            row0.HeightInPoints = 30;//行高
            row0.CreateCell(0).SetCellValue(name);//建立第一列
            IFont font = workbook.CreateFont(); //建立一個字型樣式物件
            font.FontHeightInPoints = 17;//字型大小
            font.Boldweight = short.MaxValue;//字型加粗
            ICellStyle style = workbook.CreateCellStyle();//建立樣式物件
            style.SetFont(font); //將字型樣式賦給樣式物件
            style.Alignment = HorizontalAlignment.Center;
            row0.Cells[0].CellStyle = style; ; //把樣式賦給單元格
            CellRangeAddress cellRangeAddress = new CellRangeAddress(0, 0, 0, colSpan);
            sheet1.AddMergedRegion(cellRangeAddress);

            IRow row1 = sheet1.CreateRow(1);
            row1.HeightInPoints = 20;//行高
            row1.CreateCell(0).SetCellValue("製表日期：" + DateTime.Now.Date.ToString("yyyy-MM-dd"));
            font = workbook.CreateFont(); //建立一個字型樣式物件
            font.FontHeightInPoints = 13;//字型大小
            font.Boldweight = short.MaxValue;//字型加粗
            style = workbook.CreateCellStyle();//建立樣式物件
            style.SetFont(font);
            row1.Cells[0].CellStyle = style;
            cellRangeAddress = new CellRangeAddress(1, 1, 0, colSpan);
            sheet1.AddMergedRegion(cellRangeAddress);
        }


        /// 把Json文字轉為實體
        public static object JsonToObject(string jsonString, object obj)
        {
            return JsonConvert.DeserializeObject(jsonString, obj.GetType());
        }

        /// <summary>
        /// 查詢引數實體
        /// </summary>
        private class QueryParmsObj
        {
            public string AreaNO { get; set; }
            public string StartTime { get; set; }
            public string EndTime { get; set; }
            public List<string> ColNames { get; set; }
        }

    }