如何使用C#打开excel并将数据写入第i行第j列单元格，请高手指教！

/// 导出数据到Excel中

         /// </summary>

         /// <param name="dt">DataTable数据源</param>

         /// <returns></returns>

         public  void  ExportToExcel(System.Data.DataTable dt)

         {

             if  (dt ==  null )  return ;

             Microsoft.Office.Interop.Excel.Application xlApp =  new  Microsoft.Office.Interop.Excel.Application();

             if  (xlApp ==  null )

             {

                 XtraMessageBox.Show( "无法创建Excel对象，可能您的电脑未安装Excel" ,  "系统提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);

                 return ;

             }

 

             System.Windows.Forms.SaveFileDialog saveDia =  new  SaveFileDialog();

             saveDia.Filter =  "Excel|*.xls" ;

             saveDia.Title =  "导出为Excel文件" ;

             if  (saveDia.ShowDialog() == System.Windows.Forms.DialogResult.OK && ! string .Empty.Equals(saveDia.FileName))

             {

                 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 =  null ;

                 long  totalCount = dt.Rows.Count;

                 long  rowRead = 0;

                 float  percent = 0;

                 string  fileName = saveDia.FileName;

 

                 //写入标题 

                 for  ( int  i = 0; i < dt.Columns.Count; i++)

                 {

                     worksheet.Cells[1, i + 1] = dt.Columns[i].ColumnName;

                     range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[1, i + 1];

                     //range.Interior.ColorIndex = 15;//背景颜色 

                     range.Font.Bold =  true ; //粗体 

                     range.HorizontalAlignment = Microsoft.Office.Interop.Excel.XlHAlign.xlHAlignCenter; //居中 

                     //加边框 

                     range.BorderAround(Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous, Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin, Microsoft.Office.Interop.Excel.XlColorIndex.xlColorIndexAutomatic,  null );

                     //range.ColumnWidth = 4.63;//设置列宽 

                     //range.EntireColumn.AutoFit();//自动调整列宽 

                     //r1.EntireRow.AutoFit();//自动调整行高 

                 }

 

                 //写入内容 

                 for  ( int  r = 0; r < dt.DefaultView.Count; r++)

                 {

                     for  ( int  i = 0; i < dt.Columns.Count; i++)

                     {

                         worksheet.Cells[r + 2, i + 1] = dt.DefaultView[r][i];

                         range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[r + 2, i + 1];

                         range.Font.Size = 9; //字体大小 

                         //加边框 

                         range.BorderAround(Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous, Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin, Microsoft.Office.Interop.Excel.XlColorIndex.xlColorIndexAutomatic,  null );

                         range.EntireColumn.AutoFit(); //自动调整列宽 

                     }

                     rowRead++;

                     percent = (( float )(100 * rowRead)) / totalCount;

                     System.Windows.Forms.Application.DoEvents();

                 }

 

                 range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideHorizontal].Weight = Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin;

                 if  (dt.Columns.Count > 1)

                 {

                     range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideVertical].Weight = Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin;

                 }

 

                 try

                 {

                     workbook.Saved =  true ;

                     workbook.SaveCopyAs(fileName);

                 }

                 catch  (Exception ex)

                 {

                     XtraMessageBox.Show( "导出文件时出错,文件可能正被打开！\n"  + ex.Message,  "系统提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);

                     return ;

                 }

 

                 workbooks.Close();

                 if  (xlApp !=  null )

                 {

                     xlApp.Workbooks.Close();

                     xlApp.Quit();

                     int  generation = System.GC.GetGeneration(xlApp);

                     System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);

                     xlApp =  null ;

                     System.GC.Collect(generation);

                 }

                 GC.Collect(); //强行销毁 

 

                 #region 强行杀死最近打开的Excel进程

                 System.Diagnostics.Process[] excelProc = System.Diagnostics.Process.GetProcessesByName( "EXCEL" );

                 System.DateTime startTime =  new  DateTime();

                 int  m, killId = 0;

                 for  (m = 0; m < excelProc.Length; m++)

                 {

                     if  (startTime < excelProc[m].StartTime)

                     {

                         startTime = excelProc[m].StartTime;

                         killId = m;

                     }

                 }

                 if  (excelProc[killId].HasExited ==  false )

                 {

                     excelProc[killId].Kill();

                 }

                 #endregion

                 XtraMessageBox.Show( "导出成功" ,  "系统提示" , MessageBoxButtons.OK, MessageBoxIcon.Information);

 

             }

         }