c# winform导出Excel

//需要注意添加引用Microsoft.Office.Interop.Excel.dll
 string fileName =DateTime.Now.Year+ DateTime.Now.Month+ DateTime.Now.Day + ".xls";
            if (showView.Rows.Count > )
            {

                string saveFileName = "";
                //bool fileSaved = false;
                SaveFileDialog saveDialog = new SaveFileDialog();
                saveDialog.DefaultExt = "xls";
                saveDialog.Filter = "Excel文件|*.xls";
                saveDialog.FileName = fileName;
                saveDialog.ShowDialog();
                saveFileName = saveDialog.FileName;
                if (saveFileName.IndexOf(":") < ) return; //被点了取消
                Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
                if (xlApp == null)
                {
                    MessageBox.Show("无法创建Excel对象，可能未安装Excel");
                    return;
                }

                Microsoft.Office.Interop.Excel.Workbooks workbooks = xlApp.Workbooks;
                Microsoft.Office.Interop.Excel.Workbook workbook = workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);
                Microsoft.Office.Interop.Excel.Worksheet worksheet = (Microsoft.Office.Interop.Excel.Worksheet)workbook.Worksheets[];//取得sheet1

                //写入标题
                for (int i = ; i < showView.ColumnCount; i++)
                {
                    worksheet.Cells[, i + ] = showView.Columns[i].HeaderText;
                }
                //写入数值
                for (int r = ; r < showView.Rows.Count; r++)
                {
                    for (int i = ; i < showView.ColumnCount; i++)
                    {
                        worksheet.Cells[r + , i + ] = showView.Rows[r].Cells[i].Value;
                    }
                    System.Windows.Forms.Application.DoEvents();
                }
                worksheet.Columns.EntireColumn.AutoFit();//列宽自适应

                if (saveFileName != "")
                {
                    try
                    {
                        workbook.Saved = true;
                        workbook.SaveCopyAs(saveFileName);
                        //fileSaved = true;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("导出文件时出错,文件可能正被打开！\n" + ex.Message);
                    }
                }
                xlApp.Quit();
                GC.Collect();//强行销毁
                MessageBox.Show(fileName + "的资料保存成功", "提示", MessageBoxButtons.OK);
            }
            else
            {
                MessageBox.Show("报表为空,无表格需要导出", "提示", MessageBoxButtons.OK);
            }