MSEXCEL.Application excelapp=new Microsoft.Office.Interop.Excel.Application();
                object objOpt = System.Reflection.Missing.Value;
                MSEXCEL.Workbook exceelDoc = excelapp.Workbooks.Open(this.saveFileDialog1.FileName, objOpt, false, objOpt, objOpt, objOpt, true, objOpt, objOpt, true, objOpt, objOpt, objOpt, objOpt, objOpt);
                MSEXCEL.Worksheet ws = (MSEXCEL.Worksheet)exceelDoc.Sheets[1];
                MSEXCEL.Range r;
                r = ws.get_Range("单元格横坐标", "单元格纵坐标");
                r.Value2 = this.comboBox1.SelectedText;
                exceelDoc.Save();