excel导出问题，请大家帮帮忙

Question

public static bool ExportForDataGridview(DataGridView DataGrid1, string fileName, bool isShowExcle)
        {            #region 导出数据到Excel表
            //建立Excel对象
           
                Excel.Application app = new Excel.Application();
                try
                {
                    if (app == null)
                    {
                        MessageBox.Show("对不起，您的电脑未安装Excel，请先安装后再进行操作！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                    app.Visible = isShowExcle;
                    Workbooks workbooks = app.Workbooks;
                    _Workbook workbook = workbooks.Add(XlWBATemplate.xlWBATWorksheet);
                    Sheets sheets = workbook.Worksheets;
                    _Worksheet worksheet = (_Worksheet)sheets.get_Item(1);
                    if (worksheet == null)
                    {
                        return false;
                    }
                    string sLen = "";
                    //取得最后一列列名
                    char H = (char)(64 + DataGrid1.ColumnCount / 26);
                    char L = (char)(64 + DataGrid1.ColumnCount % 26);
                    if (DataGrid1.ColumnCount < 26)
                    {
                        sLen = L.ToString();
                    }
                    else
                    {
                        sLen = H.ToString() + L.ToString();
                    }
                    //标题
                    string sTmp = sLen + "1";
                    Range ranCaption = worksheet.get_Range(sTmp, "A1");
                    string[] asCaption = new string[DataGrid1.ColumnCount];
                    for (int i = 0; i < DataGrid1.ColumnCount; i++)
                    {
                        asCaption[i] = DataGrid1.Columns[i].HeaderText;
                    }
                    ranCaption.Value2 = asCaption;                    //数据
                    object[] obj = new object[DataGrid1.Columns.Count];
                    for (int r = 0; r < DataGrid1.RowCount - 1; r++)
                    {
                        for (int l = 0; l < DataGrid1.Columns.Count; l++)
                        {
                            if (DataGrid1[l, r].ValueType == typeof(DateTime))
                            {
                                obj[l] = DataGrid1[l, r].Value.ToString();
                            }
                            else
                            {
                                obj[l] = DataGrid1[l, r].Value;
                            }
                        }
                        string cell1 = sLen + ((int)(r + 2)).ToString();
                        string cell2 = "A" + ((int)(r + 2)).ToString();
                        Range ran = worksheet.get_Range(cell1, cell2);
                        ran.Value2 = obj;
                    }
                    MessageBox.Show("恭喜，导出Excel表成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    //保存
                    workbook.SaveCopyAs(fileName);
                    workbook.Saved = true;                }
                catch(Exception ex)
                {
                    MessageBox.Show(ex.ToString());
                     MessageBox.Show("对不起，导出Excel表失败！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                finally
                {
                    //关闭
                    app.UserControl = false;
                    app.Quit();
                }
                return true;
            #endregion
        }
 private void btnOut_Click(object sender, EventArgs e)
        {
            //导出数据
            if (MessageBox.Show("数据导出功能需要专业人员技术支持，请慎重操作！您确定要将Excel表里面的数据导入到数据库里面么？", "提示", MessageBoxButtons.OKCancel, MessageBoxIcon.Exclamation) == DialogResult.OK)
            {    ExportForDataGridview(DataGrid1,"路径名称", false);              }
        }