winform 从DataGridView导出Excel

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从DataGridView导出Excel

        public static void ExportExcel(string fileName, DataGridView dgv, string fontname, short fontsize)
        {
            IWorkbook workbook;
            ISheet sheet;
            Stopwatch sw = null;

            //判断datagridview中内容是否为空
            if (dgv.Rows.Count == 0)
            {
                MessageBox.Show("DataGridView中内容为空,请先导入数据!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }

            //保存文件
            string saveFileName = "";
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            saveFileDialog.DefaultExt = "xlsx";
            saveFileDialog.Filter = "Excel文件(*.xlsx)|*.xlsx|Excel文件(*.xls)|*.xls";
            saveFileDialog.RestoreDirectory = true;
            saveFileDialog.Title = "Excel文件保存路径";
            saveFileDialog.FileName = fileName;
            MemoryStream ms = new MemoryStream(); //MemoryStream
            if (saveFileDialog.ShowDialog() == DialogResult.OK)
            {
                //**程序开始计时**//
                sw = new Stopwatch();
                sw.Start();

                saveFileName = saveFileDialog.FileName;

                //检测文件是否被占用
                if (!CheckFiles(saveFileName))
                {
                    MessageBox.Show("文件被占用,请关闭文件" + saveFileName);
                    workbook = null;
                    ms.Close();
                    ms.Dispose();
                    return;
                }
            }
            else
            {
                workbook = null;
                ms.Close();
                ms.Dispose();
            }

            //*** 根据扩展名xls和xlsx来创建对象
            string fileExt = Path.GetExtension(saveFileName).ToLower();
            if (fileExt == ".xlsx")
            {
                workbook = new XSSFWorkbook();
            }
            else if (fileExt == ".xls")
            {
                workbook = new HSSFWorkbook();
            }
            else
            {
                workbook = null;
            }
            //***

            //创建Sheet
            if (workbook != null)
            {
                sheet = workbook.CreateSheet("Sheet1");//Sheet的名称  
            }
            else
            {
                return;
            }

            //设置单元格样式
            ICellStyle cellStyle = workbook.CreateCellStyle();
            //水平居中对齐和垂直居中对齐
            cellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;
            cellStyle.VerticalAlignment = NPOI.SS.UserModel.VerticalAlignment.Center;
            //设置字体
            IFont font = workbook.CreateFont();
            font.FontName = fontname;//字体名称
            font.FontHeightInPoints = fontsize;//字号
            font.Color = NPOI.HSSF.Util.HSSFColor.Black.Index;//字体颜色
            cellStyle.SetFont(font);

            //添加列名
            IRow headRow = sheet.CreateRow(0);
            for (int i = 0; i < dgv.Columns.Count; i++)
            {
                //隐藏行列不导出
                if (dgv.Columns[i].Visible == true)
                {
                    headRow.CreateCell(i).SetCellValue(dgv.Columns[i].HeaderText);
                    headRow.GetCell(i).CellStyle = cellStyle;
                }
            }

            //根据类型写入内容
            for (int rowNum = 0; rowNum < dgv.Rows.Count; rowNum++)
            {
                ///跳过第一行,第一行为列名
                IRow dataRow = sheet.CreateRow(rowNum + 1);
                for (int columnNum = 0; columnNum < dgv.Columns.Count; columnNum++)
                {
                    int columnWidth = sheet.GetColumnWidth(columnNum) / 256; //列宽

                    //隐藏行列不导出
                    if (dgv.Rows[rowNum].Visible == true && dgv.Columns[columnNum].Visible == true)
                    {
                        //防止行列超出Excel限制
                        if (fileExt == ".xls")
                        {
                            //03版Excel最大行数是65536行,最大列数是256列
                            if (rowNum > 65536)
                            {
                                MessageBox.Show("行数超过Excel限制!");
                                return;
                            }
                            if (columnNum > 256)
                            {
                                MessageBox.Show("列数超过Excel限制!");
                                return;
                            }
                        }
                        else if (fileExt == ".xlsx")
                        {
                            //07版Excel最大行数是1048576行,最大列数是16384列
                            if (rowNum > 1048576)
                            {
                                MessageBox.Show("行数超过Excel限制!");
                                return;
                            }
                            if (columnNum > 16384)
                            {
                                MessageBox.Show("列数超过Excel限制!");
                                return;
                            }
                        }

                        ICell cell = dataRow.CreateCell(columnNum);
                        if (dgv.Rows[rowNum].Cells[columnNum].Value == null)
                        {
                            cell.SetCellType(CellType.Blank);
                        }
                        else
                        {
                            cell.SetCellValue(dgv.Rows[rowNum].Cells[columnNum].Value.ToString());
                            //    if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.Int32"))
                            //{
                            //    cell.SetCellValue(Convert.ToInt32(dgv.Rows[rowNum].Cells[columnNum].Value));
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.String"))
                            //{
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.Single"))
                            //{
                            //    cell.SetCellValue(Convert.ToSingle(dgv.Rows[rowNum].Cells[columnNum].Value));
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.Double"))
                            //{
                            //    cell.SetCellValue(Convert.ToDouble(dgv.Rows[rowNum].Cells[columnNum].Value));
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.Decimal"))
                            //{
                            //    cell.SetCellValue(Convert.ToDouble(dgv.Rows[rowNum].Cells[columnNum].Value));
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.DateTime"))
                            //{
                            //    cell.SetCellValue(Convert.ToDateTime(dgv.Rows[rowNum].Cells[columnNum].Value).ToString("yyyy-MM-dd"));
                            //}
                            //else if (dgv.Rows[rowNum].Cells[columnNum].ValueType.FullName.Contains("System.DBNull"))
                            //{
                            //    cell.SetCellValue("");
                            //}
                        }

                        //设置列宽
                        IRow currentRow;
                        if (sheet.GetRow(rowNum) == null)
                        {
                            currentRow = sheet.CreateRow(rowNum);
                        }
                        else
                        {
                            currentRow = sheet.GetRow(rowNum);
                        }

                        if (currentRow.GetCell(columnNum) != null)
                        {
                            ICell currentCell = currentRow.GetCell(columnNum);
                            int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;

                            if (columnWidth < length)
                            {
                                columnWidth = length + 10; //设置列宽数值
                            }
                        }
                        sheet.SetColumnWidth(columnNum, columnWidth * 256);

                        //单元格样式
                        dataRow.GetCell(columnNum).CellStyle = cellStyle;
                    }
                }
            }

            //保存为Excel文件                  
            workbook.Write(ms, true);
            FileStream file = new FileStream(saveFileName, FileMode.Create);
            workbook.Write(file, true);
            file.Close();
            workbook = null;
            ms.Close();
            ms.Dispose();

            //**程序结束计时**//
            sw.Stop();
            double totalTime = sw.ElapsedMilliseconds / 1000.0;

            MessageBox.Show(fileName + " 导出成功\n耗时" + totalTime + "s", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }