C# Winform datagridview导出EXCEL

string saveFileName = "";
            //bool fileSaved = false;
            SaveFileDialog saveDialog = new SaveFileDialog();
            saveDialog.DefaultExt = "xls";
            saveDialog.Filter = "Excel文件|*.xls";
            saveDialog.ShowDialog();
            saveFileName = saveDialog.FileName;
            if (saveFileName.IndexOf(":") < 0) 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，可能您的机子未安装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[1];//取得sheet1
            Microsoft.Office.Interop.Excel.Range range;
            object oMis = System.Reflection.Missing.Value;

            //显示为文本格式
            range = worksheet.Range[worksheet.Cells[1, 1], worksheet.Cells[dataGridView1.RowCount + 1, dataGridView1.ColumnCount]];
            range.NumberFormatLocal = "@";

            //写入标题
            for (int i = 0; i < dataGridView1.ColumnCount; i++)
            {
                worksheet.Cells[1, i + 1] = dataGridView1.Columns[i].HeaderText;
            }
            //写入数值
            for (int r = 0; r < dataGridView1.Rows.Count; r++)
            {
                for (int i = 0; i < dataGridView1.ColumnCount; i++)
                {
                    worksheet.Cells[r + 2, i + 1] = dataGridView1.Rows[r].Cells[i].Value;
                }
                System.Windows.Forms.Application.DoEvents();
            }
            worksheet.Columns.EntireColumn.AutoFit();//列宽自适应
            //if (Microsoft.Office.Interop.cmbxType.Text != "Notification")
            //{
            //    Excel.Range rg = worksheet.get_Range(worksheet.Cells[2, 2], worksheet.Cells[ds.Tables[0].Rows.Count + 1, 2]);
            //    rg.NumberFormat = "00000000";
            //}

            if (saveFileName != "")
            {
                try
                {
                    workbook.Saved = true;
                    workbook.SaveCopyAs(saveFileName);
                }
                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("保存成功", "提示", MessageBoxButtons.OK);