ArrayList导出excel问题，为何占用巨大大内存，有无解决方法？

Question

你这是用COM的方式，是有点消耗资源。主要还是你的代码有问题workbooks.Close(false, Nothing, Nothing);
excel.Workbooks.Close();
excel.Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(workbooks);
System.Runtime.InteropServices.Marshal.ReleaseComObject(excel);workbooks=null;
excel=null; GC.Collect();

Answer 1

excel占用的内存没有被释放掉。最好的方法是直接生成XML文件，因为从office 2003开始，excel可以读xml文件了。

Answer 2

private void exportToExcelReportFile(DataTable ds, string fileName, string rptName)
    {
        string filesPath = "";
        System.IO.StreamWriter excelDoc;
        excelDoc = new System.IO.StreamWriter(fileName);
        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=\"Center\"/>\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=\"0.00\"/>\r\n </Style>\r\n " +
              "<Style ss:ID=\"Integer\">\r\n <NumberFormat " +
              "ss:Format=\"0\"/>\r\n </Style>\r\n <Style " +
              "ss:ID=\"DateTimeLiteral\">\r\n <NumberFormat " +
              "ss:Format=\"mm/dd/yyyy hh:mm AM/PM\"/>\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>";
        string rptNames = "";
        int rowCount = 0;
        int sheetCount = 1;
        excelDoc.Write(startExcelXML);
        excelDoc.Write("<Worksheet ss:Name=\"Sheet" + sheetCount + "\">");
        excelDoc.Write("<Table>");
        //Add Sql Where Infomation
        excelDoc.Write("<Row>");
        excelDoc.Write("<Cell ss:StyleID=\"BoldColumn\"><Data ss:Type=\"String\">");
        excelDoc.Write(oneAndEightTitleInfo);
        excelDoc.Write("</Data></Cell>");
        excelDoc.Write("</Row>");
        excelDoc.Write("<Row>");
        for (int x = 0; x < ds.Columns.Count; x++)
        {
            excelDoc.Write("<Cell ss:StyleID=\"BoldColumn\"><Data ss:Type=\"String\">");
            excelDoc.Write(ds.Columns[x].ColumnName);
            excelDoc.Write("</Data></Cell>");
        }
        excelDoc.Write("</Row>");
        rptNames = rptNames + ".xml";
        filesPath = Request.PhysicalApplicationPath + directoryPath + rptName;
        foreach (DataRow x in ds.Rows)
        {
            rowCount++;
            //if the number of rows is > 64000 create a new page to continue output
            if (rowCount == 64000)
            {
                rowCount = 0;
                sheetCount++;
                excelDoc.Write("</Table>");
                excelDoc.Write(" </Worksheet>");
                excelDoc.Write("<Worksheet ss:Name=\"Sheet" + sheetCount + "\">");
                excelDoc.Write("<Table>");
            }
            excelDoc.Write("<Row>"); //ID=" + rowCount + "
            for (int y = 0; y < ds.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 < 10 ? "0" + XMLDate.Month.ToString() : XMLDate.Month.ToString()) + "-" + (XMLDate.Day < 10 ? "0" +
                             XMLDate.Day.ToString() : XMLDate.Day.ToString()) + "T" +
                             (XMLDate.Hour < 10 ? "0" + XMLDate.Hour.ToString() : XMLDate.Hour.ToString()) + ":" +
                             (XMLDate.Minute < 10 ? "0" + XMLDate.Minute.ToString() : XMLDate.Minute.ToString());
                        if (XMLDate.Hour > 0 | XMLDate.Minute > 0)
                        {
                            excelDoc.Write("<Cell ss:StyleID=\"DateTimeLiteral\">" +
                                         "<Data ss:Type=\"DateTime\">");
                        }
                        else
                        {
                            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();
    }

Answer 3

也可以创建了excel文件后，用数据库连接的方式往里面灌数据。用OleDb连接。我往excel文件读写数据都是这么做的。

Answer 4

对了，Sheet就是表名，不过写的时候是$Sheet或者是Sheet$，记不清楚了。

Answer 5

感觉慢的原因是频繁的拆箱,使用ArrayList的效率本身就不高.楼住看是否可以用数组.
com组件的编程,可以直接用数组填充一个sheet的Range.

Answer 6

为什么存成那样?
Csv不是更好?