DataSet导出Excel（ XML文件 多个SHEET）

public void ExportXML(DataSet ds, string[] sheetName,bool autoAddTitle, string fileName)
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder();

            sb.Append(" <?xml version=\"1.0\" encoding=\"utf-8\"?>");
            sb.Append(" <?mso-application progid=\"Excel.Sheet\"?>");
            sb.Append(" <Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"");
            sb.Append("  xmlns:o=\"urn:schemas-microsoft-com:office:office\"");
            sb.Append("  xmlns:x=\"urn:schemas-microsoft-com:office:excel\"");
            sb.Append("  xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\"");
            sb.Append("  xmlns:html=\"http://www.w3.org/TR/REC-html40\">");
            sb.Append(" <DocumentProperties xmlns=\"urn:schemas-microsoft-com:office:office\">");
            sb.Append("  <Author>Dean</Author>");
            sb.Append("  <Created>" + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + "</Created>");
            sb.Append("  <Company>SAE</Company>");
            sb.Append("  <Version>1.0</Version>");
            sb.Append(" </DocumentProperties>");
            sb.Append(" <ExcelWorkbook xmlns=\"urn:schemas-microsoft-com:office:excel\">");
            sb.Append("  <ProtectStructure>False</ProtectStructure>");
            sb.Append("  <ProtectWindows>False</ProtectWindows>");
            sb.Append(" </ExcelWorkbook>");
            sb.Append(" <Styles>");
            sb.Append("  <Style ss:ID=\"s01\">");
            sb.Append("   <Interior ss:Color=\"#FFFF00\" ss:Pattern=\"Solid\"/>");
            sb.Append("  </Style>");
            sb.Append(" </Styles>");

            string cellType = "";
            for (int num = 0; num < ds.Tables.Count; num++)
            {
                sb.Append(" <Worksheet ss:Name='" + sheetName[num] + "'>");
                sb.Append(" <Table ss:ExpandedColumnCount='" + ds.Tables[num].Columns.Count + "' ss:ExpandedRowCount='" + ds.Tables[num].Rows.Count + 1 + "' x:FullColumns='1' x:FullRows='1'>");//ExpandedRowCount一定不能小于实际总行数，否则报错：This file is corrupt and cannot be opened.

                if (autoAddTitle)
                {
                    sb.Append(" <Row>");
                    foreach (DataColumn dc in ds.Tables[num].Columns)
                    {
                        sb.Append(" <Cell><Data ss:Type='String'>" + dc.ColumnName + "</Data></Cell>");
                    }
                    sb.Append(" </Row>");
                }

                for (int i = 0; i < ds.Tables[num].Rows.Count; i++)
                {
                    sb.Append(" <Row>");
                    for (int j = 0; j < ds.Tables[num].Columns.Count; j++)
                    {
                        cellType = ds.Tables[num].Rows[i][j].GetType().ToString();
                       
                        if (cellType == "System.Decimal" || cellType == "System.Double" || cellType == "System.Int16" || cellType == "System.Int32" || cellType == "System.Int64" || cellType == "System.Byte")
                            //sb.Append(" <Cell><Data ss:Type='Number'>" + ds.Tables[num].Rows[i][j].ToString() + "</Data></Cell>");
                            sb.Append(" <Cell ss:StyleID=\"s01\"><Data ss:Type='Number'>" + ds.Tables[num].Rows[i][j].ToString() + "</Data></Cell>");//添加颜色等style
                        else
                            sb.Append(" <Cell><Data ss:Type='String'>" + ds.Tables[num].Rows[i][j].ToString() + "</Data></Cell>");
                    }
                    sb.Append(" </Row>");
                }

                //sb.Append(" <Row><Cell><Data ss:Type='Number'>23</Data></Cell><Cell><Data ss:Type='Number'>11</Data></Cell><Cell ss:Formula=\"=RC[-2]+RC[-1]\"><Data ss:Type='Number'>34</Data></Cell></Row>");//添加公式
                sb.Append(" </Table>");
                sb.Append(" </Worksheet>");
            }

            sb.Append(" </Workbook>");

            saveFile(sb, "application/vnd.ms-excel", fileName);
        }

        public void saveFile(System.Text.StringBuilder sb,string fileType,string fileName)
        {
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(System.Text.Encoding.UTF8.GetBytes(fileName + ".xls")));
            Response.ContentType = fileType;
            Response.ContentEncoding = System.Text.Encoding.UTF8;
            Response.Write(sb.ToString());
            Response.Flush();
            Response.End();
        }

注：
可以添加颜色，公式，合并单元格等；
具体可以创建一个EXCEL文件，里面输入数据，保存为XML文件，然后用记事本打开此XML文件，即可看到里面的内容