如果使用 ExcelDataReader 包，如何提高 Excel 文件读取速度？

Question

I'm using ExcelDataReader for reading excel files (*.xlsx, *.xlsb, *.xls) and i'm trying to speed up the process of it.

It works perfectly fine, but it takes time to display rows. To note : I'm using a big excel file (14000 rows) and I just want to display the first five.

Here my progress :

    FileInfo fileInfo = new FileInfo(filePath);
    if (fileInfo.Extension.ToLower().Contains(".xls"))
                {
                    using (FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read))
                    {
                        using (var excelReader = ExcelReaderFactory.CreateReader(stream))
                        {
                            DataTable result = excelReader.AsDataSet().Tables[0];
                            for (int i = 0; i < 6; i++)
                            {
                                resultList.Add(string.Join(",", result.Rows[i].ItemArray).Split(',').ToArray());
                            }
                            excelReader.Close();
                        }
                    }
                }
                return resultList;

Answer 1

Don't use reader.AsDataSet() - that will load the whole file into memory which has a big overhead. Instead use the reader APIs like reader.Read() to read one row at a time, and reader.GetValue() to get the values on the current row.