asp.net (jquery easy-ui datagrid)通用Excel文件導出（NPOI）

NPOI導出Excel文件的文章很多了，但是沒看到easy-ui datagrid表格直接導出Excel文件的，要顯示中文Title和Excel文件每列列寬和頁面上看到的基本相符。這里可能是個實現，不是最佳，寫出來給有用的人參考。可能在通用二字上做得還不是特別好，有好的方法請留言指正。

效果：

 

 

 

 

編碼過程：

1、js

//-----------------------------------------------------
// @description 返回grid的(可見的)所有行給后端導出Excel用
// @param {string} table    表格ID
// @returns rows
// @author 肖峰
//------------------------------------------------------
function getGridDataToExcelExport(table) {
    var allRows = $("#" + table).datagrid("getRows");
    return allRows;
}

//-----------------------------------------------------
// @description 返回grid的所有列
// @param {string} table    表格ID
// @returns rows
// @author 肖峰
function getGridColumnFields(table) {
    var allCols = $("#" + table).datagrid("getColumnFields");
    return allCols;
}

//-----------------------------------------------------
// @description 返回grid的所有列的選項title、列寬等
// @param {string} table    表格ID
// @returns rows
// @author 肖峰
function getGridColumnFieldsOptions(table) {
    var allColsTitle = $("#" + table).datagrid("options").columns;
    return allColsTitle;
}



        //導出結果集到Excel
        function exportGrid() {
            if (getGridDataToExcelExport("ResultGrid").length == 0) {
                alertMsg("系統提示", "記錄數為0，不需要導出！", "error");
                return;
            }
            var entity = {};
            entity.GridRows = getGridDataToExcelExport("ResultGrid");
            entity.GridColumnOptions = getGridColumnFieldsOptions("ResultGrid");
            entity.ExportFileName = '產品箱盒對應查詢結果.xls';
            POVOS.BarCode.Website.BoxCorrespondingQuery.ExportGridToExcelFileAndDownload(entity, function (p) {
                location.href = "ExportExcelFile.ashx?ExcelFileID=" + p.value;
            });
        }

//導出結果集到Excel
        function exportGrid() {
            if (getGridDataToExcelExport("ResultGrid").length == 0) {
                alertMsg("系統提示", "記錄數為0，不需要導出！", "error");
                return;
            }
            var entity = {};
            entity.GridRows = getGridDataToExcelExport("ResultGrid");          
            entity.GridColumnOptions = getGridColumnFieldsOptions("ResultGrid");
            entity.ExportFileName = '產品物流流向查詢結果.xls';           
            POVOS.BarCode.Website.ProductTransQuery.ExportGridToExcelFileAndDownload(entity, function (p) {               
                location.href = "ExportExcelFile.ashx?ExcelFileID="+p.value;
            });
        }

2、后台代碼，前台使用ajaxpro2調用后台方法，傳遞前端頁面grid行列記錄的Json格式。

/// <summary>
        /// 形成Excel對應的文件流存在數據庫里，返回給前端File GUID
        /// </summary>
        /// <param name="entity"></param>
        /// <returns></returns>
        [AjaxMethod]
        public string ExportGridToExcelFileAndDownload(JavaScriptObject entity)
        {
            var gridRows = (JavaScriptArray)entity["GridRows"];
            var gridOptions = (JavaScriptArray)entity["GridColumnOptions"];
            var gridOptionList = (JavaScriptArray)gridOptions[0];
            //可見的列
            List<JavaScriptObject> gridCols = new List<JavaScriptObject>();
            foreach (JavaScriptObject j in gridOptionList)
            {
                if (j.Value.IndexOf("hidden") == -1)
                {
                    gridCols.Add(j);
                }
            }
            var fileName = entity["ExportFileName"].ToString();           
            string tempFileName = AppDomain.CurrentDomain.BaseDirectory + "CommonExcelFile.xls";
            FileStream fs = new FileStream(tempFileName, FileMode.Open, FileAccess.Read);
            var workBook = new HSSFWorkbook(fs);
            workBook.SetSheetName(0,"查詢結果");
            var sheet = workBook.GetSheetAt(0); 
            //表頭(列)，第一行
            int newColIndex = 0;
            var titleRow = sheet.CreateRow(newColIndex);
            int cIndex = 0;
            foreach (JavaScriptObject j in gridCols)
            {
                titleRow.CreateCell(cIndex).SetCellValue(j["title"].ToString());
                int width = int.Parse(j["width"].ToString()) / 6;
                if (width > 255)
                    width = 250;
                sheet.SetColumnWidth(cIndex, width*256);
                cIndex++;
            }
            //行記錄
            for (int rowIndex = 0; rowIndex < gridRows.Count; rowIndex++)
            {
                newColIndex++;
                var row = sheet.CreateRow(newColIndex);
                var jsonEntity = gridRows[rowIndex] as JavaScriptObject;
                for (int colIndex = 0; colIndex < gridCols.Count; colIndex++)
                {
                    string cellValue = string.Empty;
                    JavaScriptObject colOption = (JavaScriptObject)gridCols[colIndex];
                    string field = colOption["field"].ToString();
                    if (jsonEntity[field] != null)
                        cellValue = jsonEntity[field].ToString();
                    row.CreateCell(colIndex).SetCellValue(cellValue);
                }
            }
            MemoryStream newFile = new MemoryStream();
            sheet.Workbook.Write(newFile);
            using (POVOSEntities db = new POVOSEntities())
            {
                var resultFile = new ExportFileEntity();
                resultFile.FileGuid = Guid.NewGuid();
                resultFile.FileName = fileName;
                resultFile.FileCreateDateTime = DateTime.Now;
                resultFile.FileStreamByte = newFile.GetBuffer();
                db.AddToExportFileEntity(resultFile);
                db.SaveChanges();
                return resultFile.FileGuid.ToString();
            }            
        }

3、文件下載使用一般處理程序，接收QueryString里傳的文件ID，返回給前端Excel文件。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.SessionState;
using NPOI.SS.UserModel;
using NPOI.HSSF.UserModel;
using BarCode.DataAccess;

namespace POVOS.BarCode.Website
{
    /// <summary>
    /// 讀取數據庫Excel文件並下載
    /// </summary>
    public class ExportExcelFile : IHttpHandler, IRequiresSessionState
    {
        public void ProcessRequest(HttpContext context)
        {
            using (POVOSEntities db = new POVOSEntities())
            {
                Guid fileID = new Guid(context.Request["ExcelFileID"] as string);
                var fileEntity = db.ExportFileEntity.Where(e => e.FileGuid == fileID).FirstOrDefault();
                string filename = string.Format("[{0}]{1}", DateTime.Now.ToString("yyMMddHHmmss"), fileEntity.FileName);
                context.Response.ContentType = "application/vnd.ms-excel";
                context.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", context.Server.UrlEncode(filename)));
                context.Response.Clear();
                context.Response.BinaryWrite(fileEntity.FileStreamByte);
                context.Response.End();
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

 

       

總結一下，遇到以下幾個問題：

1、如何傳遞datagrid的行列記錄到后置代碼里，形成Excel文件。

2、NPOI的使用，如果控制列寬，對齊樣式等。

3、下載時文件名顯示為亂碼。

4、解析前端頁面傳遞過來的JSON，比如某些列沒有"hidden"選項等。