Winform開發遇到的問題之DataGridView導出Excel

1.代碼塊：

//Excel導出功能
       public static void ExportExcel(string fileName, DataGridView dgv)
        {
            if (dgv.Rows.Count > )
            {

                string saveFileName = "";
                bool fileSaved = false;
                SaveFileDialog saveDialog = new SaveFileDialog();
                saveDialog.DefaultExt = "xlsx";
                saveDialog.Filter = "Excel檔案|*.xlsx";
                saveDialog.FileName = fileName;
                saveDialog.ShowDialog();
                saveFileName = saveDialog.FileName;
                if (saveFileName.IndexOf(":") < ) return; //被點了取消   
                Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
                if (xlApp == null)
                {
                    MessageBox.Show("無法建立Excel對象，可能您的機子未安裝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  

                //寫入标題  
                for (int i = ; i < dgv.ColumnCount; i++)
                {
                    worksheet.Cells[, i + ] = dgv.Columns[i].HeaderText;
                }
                //寫入數值  
                for (int r = ; r < dgv.Rows.Count; r++)
                {
                    for (int i = ; i < dgv.ColumnCount; i++)
                    {
                        worksheet.Cells[r + , i + ] = dgv.Rows[r].Cells[i].Value;
                    }
                    System.Windows.Forms.Application.DoEvents();
                }
                worksheet.Columns.EntireColumn.AutoFit();//列寬自适應                  
                if (saveFileName != "")
                {
                    try
                    {
                        workbook.Saved = true;
                        workbook.SaveCopyAs(saveFileName);
                        fileSaved = true;
                    }
                    catch (Exception ex)
                    {
                        fileSaved = false;
                        MessageBox.Show("導出檔案時出錯,檔案可能正被打開！\n" + ex.Message);
                    }

                }
                else
                {
                    fileSaved = false;
                }
                xlApp.Quit();
                GC.Collect();//強行銷毀                                              
                if (DialogResult.Yes == MessageBox.Show("是否需要打開此檔案!", "提示", MessageBoxButtons.YesNo))
                {
                    if (fileSaved && System.IO.File.Exists(saveFileName)) System.Diagnostics.Process.Start(saveFileName); //打開EXCEL 
                }
                else
                {
                 MessageBox.Show(fileName + "刷卡記錄儲存成功!", "提示", MessageBoxButtons.OK);
                }
            }
            else
            {
                MessageBox.Show("報表為空,無表格需要導出", "提示", MessageBoxButtons.OK);
            }

        }
        //調用[綁定按鈕事件]
        private void btn_LatelyCurrent_Click(object sender, EventArgs e)
        {
            var date = DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss");
            date = "SKJL_"+date;
            //date:檔案名稱；dgStaff1:DataGridView控件名稱
            ExportExcel(date, dgStaff1);
        }
           

2.效果圖：

3.Excel檔案：