C#中如何将DataTable中的数据写入Excel

    /// <summary>
    /// 把DataTable导入到Excel中
    /// </summary>
    /// <param name="tableName"> 表的名字 </param>
    /// <param name="result"> 要导入的DataTable </param>
    public   String OuterPutExcel(String tableName, DataTable result, int num)
    {
        oExcel = new Excel.ApplicationClass();
        DataTable dt = new DataTable(); // 按客户出货日月统计表
        StringBuilder build = new StringBuilder();
        build.Append(Server.MapPath(Request.ApplicationPath)).Append( " \\App_Data\\ " ).Append(DateTime.Now.Year.ToString()).Append( " 年- " ).Append(DateTime.Now.Month).Append( " 月- " ).Append(DateTime.Now.Day.ToString()).Append( " 日 " ).Append( " 成品报表.xls " );
        sFile = build.ToString();
        if (num == 1 ) // 第一次调用,判断是否有今天的成品报表,有此删除,添加新Excel文件.
        {
            if (File.Exists(sFile))
                File.Delete(sFile); //    '删除服务端临时文件
            oExcel.Workbooks.Add(Type.Missing); // 添加一个新的工作薄;
            Excel.Workbook activeBook = (Excel.Workbook)oExcel.ActiveWorkbook;
            activeBook.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlNoChange, Type.Missing, false , Type.Missing, Type.Missing, Type.Missing); // 新建一个Excel文件;
        }
        oExcel.Visible = true ;
        oExcel.DisplayAlerts = false ;
        // '定义一个新的工作簿
        oBooks = oExcel.Workbooks; //
        oBooks.Open(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
        oBook = oBooks[ 1 ];
        // oBook.Protect(Type.Missing, true, true); // 设置工作簿保护
        oSheets = oBook.Worksheets;
        try
        {
            // 把导入的数据表插入到适当的位置
            for ( int i = 0 ; i < oSheets.Count; i ++ )
            {
                oSheet = (Excel.Worksheet)oSheets[i + 1 ];
                // oSheet.Protect(Type.Missing, Type.Missing, Type.Missing, Type.Missing, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, false); // 工作表保护;
                oCells = oSheet.Cells;
                if (oSheet.Name.ToLower().Trim() == tableName.ToLower().Trim() || tableName == " 发货--按工厂分 " || tableName == " 发货--按客户分 " )
                {
                    if (tableName == " 发货--按客户分 " )
                        oSheet.Name = " 发货--按客户分 " ;
                    else if (tableName == " 发货--按工厂分 " )
                    {
                        oSheet = (Excel.Worksheet)oSheets[ 2 ]; // 第二个工作表
                        oSheet.Name = " 发货--按工厂分 " ;
                        oCells = oSheet.Cells;
                    }
                    oCells.Clear();
                    DumpData(result, oCells); // 在Excel中写数据.
                    oSheet.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                    // oExcel.ActiveWorkbook.Close(true, sTemplate, null); // 关闭 Excel 文件且保存Excel文件
                    break ; // 跳出循环
                }
                if (i == oSheets.Count - 1 ) // 在原来的表中找不到此工作表.
                {
                    if (tableName == " 发货--按工厂分 " ) // 插入到第一个工作表中
                    {
                        oSheets.Add((Excel.Worksheet)oSheets[ 1 ], Type.Missing, Type.Missing, Type.Missing); // 插入的工作表
                        oSheet = oBook.ActiveSheet as Excel.Worksheet;
                        oSheet.Name = " 发货--按工厂分 " ;
                        oCells = oSheet.Cells;
                        oCells.Clear();
                        DumpData(result, oCells); // 在Excel中写数据.
                        oSheet.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                        break ;
                    }
                    else if (tableName == " 发货--按客户分 " ) // 插入到第二个工作表中
                    {
                        oSheets.Add((Excel.Worksheet)oSheets[ 2 ], Type.Missing, Type.Missing, Type.Missing); // 插入的工作表
                        oSheet = oBook.ActiveSheet as Excel.Worksheet;
                        oSheet.Name = " 发货--按客户分 " ;
                        oCells = oSheet.Cells;
                        oCells.Clear();
                        DumpData(result, oCells); // 在Excel中写数据.
                        oSheet.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                        // oBook.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                        break ;
                    }
                    else // 插入到第三个工作表之后.
                    {
                        if (oSheet.Name.ToLower() == " sheet3 " )
                        {
                            oSheet.Name = tableName;
                            oCells = oSheet.Cells;
                            oCells.Clear();
                            DumpData(result, oCells); // 在Excel中写数据.
                            oSheet.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                            // oBook.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);       
                            break ;
                        }
                        oSheets.Add(Type.Missing, (Excel.Worksheet)oSheets[oSheets.Count], Type.Missing, Type.Missing); // 插入的工作表
                        oSheet = oBook.ActiveSheet as Excel.Worksheet;
                        oSheet.Name = tableName;
                        oCells = oSheet.Cells;
                        oCells.Clear();
                        DumpData(result, oCells); // 在Excel中写数据.
                        oSheet.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                        // oBook.SaveAs(sFile, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);       
                        break ;
                    }
                }

            }
        }
        catch (System.Exception ex)
        {
            System.Diagnostics.Process myproc = new System.Diagnostics.Process(); //
            System.Diagnostics.Process[] proc = System.Diagnostics.Process.GetProcessesByName( " excel " );
            foreach (System.Diagnostics.Process process in proc)
            {
                if ( ! process.CloseMainWindow())
                {
                    process.Kill();
                }
            }

        }
        finally
        {

            oBook.Close(Type.Missing, Type.Missing, Type.Missing);
            // '退出Excel，并且释放调用的COM资源
            oExcel.Quit();
            Marshal.ReleaseComObject(oCells); Marshal.ReleaseComObject(oSheet);
            Marshal.ReleaseComObject(oSheets); Marshal.ReleaseComObject(oBook);
            Marshal.ReleaseComObject(oBooks); Marshal.ReleaseComObject(oExcel);
            oExcel = null ; oBooks = null ; oBook = null ;
            oSheets = null ; oSheet = null ; oCells = null ;
                     System.GC.Collect();
        }
        /* 这里用到个goto语句,是因为: 线程是异步执行的,下面的代码要访问download.xls文件,但有
       少数情况下上面的线程'未能及时释放download.xls文件的指针,那么下面代码执行语句时会抛出异常, 当发生异常时需要等待资源释放后,'再重新访问该文件, 保证下载文件能够正确下载 */
        return sFile;