datagridview 导出 Excel

1.下载NPOI.dll并添加引用

2.封装需要调用的方法 （直接复制下面代码即可，根据需要稍加改动）

 public class NPOIHelper
    {
        /// <summary>
        /// DataTable导出到Excel文件
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <param name="strFileName">保存位置</param>
        public static void Export(DataTable dtSource, string strHeaderText, string FileName)
        {
            using (MemoryStream ms = Export(dtSource, strHeaderText))
            {
                using (FileStream fs = new FileStream(FileName, FileMode.Create, FileAccess.Write))
                {
                    byte[] data = ms.ToArray();
                    fs.Write(data, 0, data.Length);
                    fs.Flush();
                }
            }
        }
        /// <summary>
        /// DataTable导出到Excel的MemoryStream
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        public static MemoryStream Export(DataTable dtSource, string strHeaderText)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet();
            #region 右击文件 属性信息
            {
                DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
                dsi.Company = "NPOI";
                workbook.DocumentSummaryInformation = dsi;

                SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
                si.ApplicationName = "导出数据";
                si.Comments = "部";
                si.Title = "导出表";
                si.Subject = "数据表";
                si.CreateDateTime = DateTime.Now;
                workbook.SummaryInformation = si;
            }
    #endregion

            HSSFCellStyle dateStyle = (HSSFCellStyle)(workbook.CreateCellStyle());
            HSSFDataFormat format = (HSSFDataFormat)(workbook.CreateDataFormat());
            dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

            //取得列宽
            int[] arrColWidth = new int[dtSource.Columns.Count];
            foreach (DataColumn item in dtSource.Columns)
            {
                arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
            }
            for (int i = 0; i < dtSource.Rows.Count; i++)
            {
                for (int j = 0; j < dtSource.Columns.Count; j++)
                {
                    int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                    if (intTemp > arrColWidth[j])
                    {
                        arrColWidth[j] = intTemp;
                    }
                }
            }
            int rowIndex = 0;
            foreach (DataRow row in dtSource.Rows)
            {
                #region 新建表，填充表头，填充列头，样式
                if (rowIndex == 65535 || rowIndex == 0)
                {
                    if (rowIndex != 0)
                    {
                        sheet = (HSSFSheet)(workbook.CreateSheet());
                    }

                    #region 表头及样式
                    {
                        HSSFRow headerRow = (HSSFRow)(sheet.CreateRow(0));
                        headerRow.HeightInPoints = 25;
                        headerRow.CreateCell(0).SetCellValue(strHeaderText);

                        HSSFCellStyle headStyle = (HSSFCellStyle)(workbook.CreateCellStyle());
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        headStyle.VerticalAlignment = VerticalAlignment.CENTER;
                        HSSFFont font = (HSSFFont)(workbook.CreateFont());
                        font.FontHeightInPoints = 20;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);
                        headerRow.GetCell(0).CellStyle = headStyle;
                        sheet.AddMergedRegion(new NPOI.SS.Util.Region(0, 0, 0, dtSource.Columns.Count - 1));
                        // headerRow.Dispose();
                    }
                    #endregion
                    #region 列头及样式
                    {
                        HSSFRow headerRow = (HSSFRow)sheet.CreateRow(1);
                        HSSFCellStyle headStyle = (HSSFCellStyle)workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        HSSFFont font = (HSSFFont)workbook.CreateFont();
                        font.FontHeightInPoints = 10;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);
                        foreach (DataColumn column in dtSource.Columns)
                        {
                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            //设置列宽
                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
                        }
                        // headerRow.Dispose();
                    }
                    #endregion

                    rowIndex = 2;
                }
                #endregion
               
                #region 填充内容
                HSSFRow dataRow = (HSSFRow)sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dtSource.Columns)
                {
                    HSSFCell newCell = (HSSFCell)dataRow.CreateCell(column.Ordinal);

                    string drValue = row[column].ToString();

                    switch (column.DataType.ToString())
                    {
                        case "System.String"://字符串类型
                            newCell.SetCellValue(drValue);
                            break;
                        case "System.DateTime"://日期类型
                            DateTime dateV;
                            DateTime.TryParse(drValue, out dateV);
                            newCell.SetCellValue(dateV);

                            newCell.CellStyle = dateStyle;//格式化显示
                            break;
                        case "System.Boolean"://布尔型
                            bool boolV = false;
                            bool.TryParse(drValue, out boolV);
                            newCell.SetCellValue(boolV);
                            break;
                        case "System.Int16"://整型
                        case "System.Int32":
                        case "System.Int64":
                        case "System.Byte":
                            int intV = 0;
                            int.TryParse(drValue, out intV);
                            newCell.SetCellValue(intV);
                            break;
                        case "System.Decimal"://浮点型
                        case "System.Double":
                            double doubV = 0;
                            double.TryParse(drValue, out doubV);
                            newCell.SetCellValue(doubV);
                            break;
                        case "System.DBNull"://空值处理
                            newCell.SetCellValue("");
                            break;
                        default:
                            newCell.SetCellValue("");
                            break;
                    }

                }
                #endregion

                rowIndex++;
            }
            using (MemoryStream ms = new MemoryStream())
            {
                workbook.Write(ms);
                ms.Flush();
                ms.Position = 0;

                //sheet.Dispose();
                //workbook.Dispose();
                return ms;
            }
        }      
    }

 

3.方法调用

 DataSet ds1 = ShowAlarmInfo(orderno, barcode, 1, starttime, endtime);
                    DataTable t_Alarm = ds1.Tables[0];
                    string headText = "高级报警信息表";
                    string filname = "高级报警信息表" + ".xls";
                    NPOIHelper.Export(t_Alarm, headText, filname);