DataSet导出到Excel文件

         public static void ExportToExcel(DataSet source, string fileName)
         {
             System.IO.StreamWriter excelDoc = new System.IO.StreamWriter(fileName);
             ExportToExcel(source, excelDoc);
         }

         public static void ExportToExcel(DataTable dtSource, string fileName)
         {
             DataSet dsSource = new DataSet();
             dsSource.Tables.Add(dtSource);

             ExportToExcel(dsSource, fileName);
         }

         public static void ExportToExcel(DataTable dtSource, System.IO.StreamWriter excelDoc)
         {
             DataSet dsSource = new DataSet();
             dsSource.Tables.Add(dtSource);

             ExportToExcel(dsSource, excelDoc);
         }

         public static void ExportToExcel(DataSet source, System.IO.StreamWriter excelDoc)
         {
             const string startExcelXML = "<xml version>\r\n<Workbook " +
                   "xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"\r\n" +
                   " xmlns:o=\"urn:schemas-microsoft-com:office:office\"\r\n " +
                   "xmlns:x=\"urn:schemas-    microsoft-com:office:" +
                   "excel\"\r\n xmlns:ss=\"urn:schemas-microsoft-com:" +
                   "office:spreadsheet\">\r\n <Styles>\r\n " +
                   "<Style ss:ID=\"Default\" ss:Name=\"Normal\">\r\n " +
                   "<Alignment ss:Vertical=\"Bottom\"/>\r\n <Borders/>" +
                   "\r\n <Font/>\r\n <Interior/>\r\n <NumberFormat/>" +
                   "\r\n <Protection/>\r\n </Style>\r\n " +
                   "<Style ss:ID=\"BoldColumn\">\r\n <Font " +
                   "x:Family=\"Swiss\" ss:Bold=\"1\"/>\r\n </Style>\r\n " +
                   "<Style     ss:ID=\"StringLiteral\">\r\n <NumberFormat" +
                   " ss:Format=\"@\"/>\r\n </Style>\r\n <Style " +
                   "ss:ID=\"Decimal\">\r\n <NumberFormat " +
                   "ss:Format=\"0\"/>\r\n </Style>\r\n " +
                   "<Style ss:ID=\"Integer\">\r\n <NumberFormat " +
                   "ss:Format=\"0\"/>\r\n </Style>\r\n <Style " +
                   "ss:ID=\"DateLiteral\">\r\n <NumberFormat " +
                   "ss:Format=\"mm/dd/yyyy;@\"/>\r\n </Style>\r\n " +
                   "</Styles>\r\n ";
             const string endExcelXML = "</Workbook>";

             int rowCount = ;
             int sheetCount = ;
             excelDoc.Write(startExcelXML);
             excelDoc.Write("<Worksheet ss:Name=\"Sheet" + sheetCount + "\">");
             excelDoc.Write("<Table>");
             excelDoc.Write("<Row>");
             for (int x = ; x < source.Tables[].Columns.Count; x++)
             {
                 excelDoc.Write("<Cell ss:StyleID=\"BoldColumn\"><Data ss:Type=\"String\">");
                 excelDoc.Write(source.Tables[].Columns[x].ColumnName);
                 excelDoc.Write("</Data></Cell>");
             }
             excelDoc.Write("</Row>");
             foreach (DataRow x in source.Tables[].Rows)
             {
                 rowCount++;
                 if (rowCount == )
                 {
                     rowCount = ;
                     sheetCount++;
                     excelDoc.Write("</Table>");
                     excelDoc.Write(" </Worksheet>");
                     excelDoc.Write("<Worksheet ss:Name=\"Sheet" + sheetCount + "\">");
                     excelDoc.Write("<Table>");
                 }
                 excelDoc.Write("<Row>");
                 for (int y = ; y < source.Tables[].Columns.Count; y++)
                 {
                     System.Type rowType;
                     rowType = x[y].GetType();
                     switch (rowType.ToString())
                     {
                         case "System.String":
                             string XMLstring = x[y].ToString();
                             XMLstring = XMLstring.Trim();
                             XMLstring = XMLstring.Replace("&", "&");
                             XMLstring = XMLstring.Replace(">", ">");
                             XMLstring = XMLstring.Replace("<", "<");
                             excelDoc.Write("<Cell ss:StyleID=\"StringLiteral\">" +
                                            "<Data ss:Type=\"String\">");
                             excelDoc.Write(XMLstring);
                             excelDoc.Write("</Data></Cell>");
                             break;
                         case "System.DateTime":
                             DateTime XMLDate = (DateTime)x[y];
                             string XMLDatetoString = "";
                             XMLDatetoString = XMLDate.Year.ToString() +
                                  "-" +
                                  (XMLDate.Month <  ? "" +
                                  XMLDate.Month.ToString() : XMLDate.Month.ToString()) +
                                  "-" +
                                  (XMLDate.Day <  ? "" +
                                  XMLDate.Day.ToString() : XMLDate.Day.ToString()) +
                                  "T" +
                                  (XMLDate.Hour <  ? "" +
                                  XMLDate.Hour.ToString() : XMLDate.Hour.ToString()) +
                                  ":" +
                                  (XMLDate.Minute <  ? "" +
                                  XMLDate.Minute.ToString() : XMLDate.Minute.ToString()) +
                                  ":" +
                                  (XMLDate.Second <  ? "" +
                                  XMLDate.Second.ToString() : XMLDate.Second.ToString()) +
                                  ".000";
                             excelDoc.Write("<Cell ss:StyleID=\"DateLiteral\">" +
                                          "<Data ss:Type=\"DateTime\">");
                             excelDoc.Write(XMLDatetoString);
                             excelDoc.Write("</Data></Cell>");
                             break;
                         case "System.Boolean":
                             excelDoc.Write("<Cell ss:StyleID=\"StringLiteral\">" +
                                         "<Data ss:Type=\"String\">");
                             excelDoc.Write(x[y].ToString());
                             excelDoc.Write("</Data></Cell>");
                             break;
                         case "System.Int16":
                         case "System.Int32":
                         case "System.Int64":
                         case "System.Byte":
                             excelDoc.Write("<Cell ss:StyleID=\"Integer\">" +
                                     "<Data ss:Type=\"Number\">");
                             excelDoc.Write(x[y].ToString());
                             excelDoc.Write("</Data></Cell>");
                             break;
                         case "System.Decimal":
                         case "System.Double":
                             excelDoc.Write("<Cell ss:StyleID=\"Decimal\">" +
                                   "<Data ss:Type=\"Number\">");
                             excelDoc.Write(x[y].ToString());
                             excelDoc.Write("</Data></Cell>");
                             break;
                         case "System.DBNull":
                             excelDoc.Write("<Cell ss:StyleID=\"StringLiteral\">" +
                                   "<Data ss:Type=\"String\">");
                             excelDoc.Write("");
                             excelDoc.Write("</Data></Cell>");
                             break;
                         default:
                             throw (new Exception(rowType.ToString() + " not handled."));
                     }
                 }
                 excelDoc.Write("</Row>");
             }
             excelDoc.Write("</Table>");
             excelDoc.Write(" </Worksheet>");
             excelDoc.Write(endExcelXML);
             excelDoc.Close();
         }