我正在尝试使用OpenXML从ASP.NET Web服务器写出Excel文件。我大约有2100条记录,大约需要20到30秒才能完成。有什么办法可以使它更快?从数据库中检索2100行只需不到一秒钟的时间。不知道为什么要在内存中处理它们会花费更多时间。
注意:ExcelWriter是我们的自定义类,但其所有方法都直接来自此链接http://msdn.microsoft.com/en-us/library/cc861607.aspx中的代码
public static MemoryStream CreateThingReport(List<Thing> things, MemoryStream template)
{
SpreadsheetDocument spreadsheet = SpreadsheetDocument.Open(template, true);
WorksheetPart workSheetPart = spreadsheet.WorkbookPart.WorksheetParts.First();
SharedStringTablePart sharedStringPart = spreadsheet.WorkbookPart.GetPartsOfType<SharedStringTablePart>().First();
Cell cell = null;
int index = 0;
//create cell formatting for header text
Alignment wrappedAlignment = new Alignment { WrapText = true };
uint rowOffset = 2;
foreach (Thing t in things)
{
//Received Date
cell = ExcelWriter.InsertCellIntoWorksheet("A", rowOffset, workSheetPart);
index = ExcelWriter.InsertSharedStringItem(t.CreateDate.ToShortDateString(), sharedStringPart);
cell.CellValue = new CellValue(index.ToString());
cell.DataType = new DocumentFormat.OpenXml.EnumValue<CellValues>(CellValues.SharedString);
//Car Part Name
cell = ExcelWriter.InsertCellIntoWorksheet("B", rowOffset, workSheetPart);
index = ExcelWriter.InsertSharedStringItem(t.CarPart.Name, sharedStringPart);
cell.CellValue = new CellValue(index.ToString());
cell.DataType = new DocumentFormat.OpenXml.EnumValue<CellValues>(CellValues.SharedString);
rowOffset++;
}
workSheetPart.Worksheet.Save();
spreadsheet.WorkbookPart.Workbook.Save();
spreadsheet.Close();
return template;
最佳答案
因此,似乎MSDN社区文档中的某人遇到了类似的性能影响。下面的代码效率很低。有人建议使用哈希表。
对于我们的解决方案,我们完全删除了共享字符串的插入,下载时间从1:03秒变为0:03秒。
//Old: (1:03)
cell = ExcelWriter.InsertCellIntoWorksheet("A", rowOffset, workSheetPart);
index = ExcelWriter.InsertSharedStringItem(thing.CreateDate.ToShortDateString(), sharedStringPart);
cell.CellValue = new CellValue(index.ToString());
cell.DataType = new DocumentFormat.OpenXml.EnumValue<CellValues>(CellValues.SharedString);
//New: (0:03)
cell = ExcelWriter.InsertCellIntoWorksheet("A", rowOffset, workSheetPart);
cell.CellValue = new CellValue(thing.CreateDate.ToShortDateString());
cell.DataType = new DocumentFormat.OpenXml.EnumValue<CellValues>(CellValues.String);
MSDN Docs(缓慢的解决方案,他们应该改用哈希表)
private static int InsertSharedStringItem(string text, SharedStringTablePart shareStringPart)
{
// If the part does not contain a SharedStringTable, create one.
if (shareStringPart.SharedStringTable == null)
{
shareStringPart.SharedStringTable = new SharedStringTable();
}
int i = 0;
// Iterate through all the items in the SharedStringTable. If the text already exists, return its index.
foreach (SharedStringItem item in shareStringPart.SharedStringTable.Elements<SharedStringItem>())
{
if (item.InnerText == text)
{
return i;
}
i++;
}
// The text does not exist in the part. Create the SharedStringItem and return its index.
shareStringPart.SharedStringTable.AppendChild(new SharedStringItem(new DocumentFormat.OpenXml.Spreadsheet.Text(text)));
shareStringPart.SharedStringTable.Save();
return i;
}
关于c# - .NET OpenXML性能问题,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/10542719/