在Excel上读取Excel文件中的有限行

Question

我在IIS上托管了一个asp.net mvc应用程序.我有一个表单,用户上传包含50k +行的excel文件.我用以下C#代码读取了excel文件.

    public DataTable GetExcelDataTable(string fileName)
    {
        string connectionString = Path.GetExtension(fileName) == "xls" ?
            string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data source={0}; Extended Properties=Excel 8.0;", fileName) :
            string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0}; Extended Properties=Excel 12.0;", fileName);

        var conn = new OleDbConnection(connectionString);
        using (var adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", conn))
        {
            var ds = new DataSet();

            adapter.Fill(ds);

            DataTable data = ds.Tables[0];

            conn.Close();
            conn.Dispose();
            adapter.Dispose();
            return data;
        }
    }

问题是它只读取多达30k行但从不读取整个excel文件.

有趣的是,如果我使用visual studio运行mvc app,我可以阅读(使用相同的代码)所有行,但是,再次,永远不会从IIS(IIS也在我的机器上)托管的网站上.

任何想法,为什么会这样？

Answer 1

在这种方法中,不需要在目标机器上安装excel

    NPOI.SS.UserModel.IWorkbook hssfworkbook;

    bool InitializeWorkbook(string path)
    {
        try
        {
            if (path.ToLower().EndsWith(".xlsx"))
            {
                FileStream file1 = File.OpenRead(path);
                hssfworkbook = new XSSFWorkbook(file1);
            }
            else
            {
                //read the template via FileStream, it is suggested to use FileAccess.Read to prevent file lock.
                //book1.xls is an Excel-2007-generated file, so some new unknown BIFF records are added. 
                using (FileStream file = new FileStream(path, FileMode.Open, FileAccess.Read))
                {
                    hssfworkbook = new HSSFWorkbook(file);
                }
            }
            return true;
        }
        catch
        {
            return false;
        }
    }

在下面的 :

public DataTable GetExcelDataTable(NPOI.SS.UserModel.IWorkbook hssfworkbook, int rowCount)
    {
        NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        DataTable dt = new DataTable();

        bool skipReadingHeaderRow = rows.MoveNext();
        if (skipReadingHeaderRow)
        {
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (NPOI.HSSF.UserModel.HSSFRow)rows.Current;
            else
                row = (NPOI.XSSF.UserModel.XSSFRow)rows.Current;
            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);
                if (cell != null)
                {
                    dt.Columns.Add(cell.ToString());
                }
                else
                {
                    dt.Columns.Add(string.Empty);
                }
            }
        }
        int cnt = 0;
        while (rows.MoveNext() && cnt < rowCount)
        {
            cnt++;
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (NPOI.HSSF.UserModel.HSSFRow)rows.Current;
            else
                row = (XSSFRow)rows.Current;

            DataRow dr = dt.NewRow();

            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);

                if (cell == null)
                {
                    dr[i - 1] = null;
                }
                else if (i > 0)
                {

                    dr[i - 1] = cell.ToString();
                }
            }
            dt.Rows.Add(dr);
        }

        return dt;
    }

要么:

     public DataTable GetExcelDataTable(NPOI.SS.UserModel.IWorkbook hssfworkbook, int rowCount)
    {

        NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();
        DataTable dt = new DataTable();
        bool skipReadingHeaderRow = rows.MoveNext();
        if (skipReadingHeaderRow)
        {
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (NPOI.HSSF.UserModel.HSSFRow)rows.Current;
            else
                row = (NPOI.XSSF.UserModel.XSSFRow)rows.Current;
            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);
                if (cell != null)
                {
                    dt.Columns.Add(cell.ToString());
                }
                else
                {
                    dt.Columns.Add(string.Empty);
                }
            }
        }
        int cnt = 0;
        while (rows.MoveNext() && cnt < rowCount)
        {
            cnt++;
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (HSSFRow)rows.Current;
            else
                row = (XSSFRow)rows.Current;
            DataRow dr = dt.NewRow();

            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);

                if (cell == null && i > 0)
                {
                    dr[i - 1] = null;
                }
                else if (i > 0)
                {
                    switch (cell.CellType)
                    {
                        case CellType.Blank:
                            dr[i - 1] = "[null]";
                            break;
                        case CellType.Boolean:
                            dr[i - 1] = cell.BooleanCellValue;
                            break;
                        case CellType.Numeric:
                            dr[i - 1] = cell.ToString();
                            break;
                        case CellType.String:
                            dr[i - 1] = cell.StringCellValue;
                            break;
                        case CellType.Error:
                            dr[i - 1] = cell.ErrorCellValue;
                            break;
                        case CellType.Formula:
                        default:
                            dr[i - 1] = "=" + cell.CellFormula;
                            break;
                    }

                }
            }
            dt.Rows.Add(dr);
        }

        return dt;
    }

要么 :

public DataTable GetExcelDataTable(NPOI.SS.UserModel.IWorkbook hssfworkbook, int segment, int rowCount)
    {
        NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0);
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        DataTable dt = new DataTable();

        bool skipReadingHeaderRow = rows.MoveNext();
        if (skipReadingHeaderRow)
        {
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (NPOI.HSSF.UserModel.HSSFRow)rows.Current;
            else
                row = (NPOI.XSSF.UserModel.XSSFRow)rows.Current;
            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);
                if (cell != null)
                {
                    dt.Columns.Add(cell.ToString());
                }
                else
                {
                    dt.Columns.Add(string.Empty);
                }
            }
        }
        for (int i = 0; i < (segment - 1)*rowCount; i++)
        {
            if (!rows.MoveNext()) break;
        }

        int cnt = 0;
        while (rows.MoveNext() && cnt < rowCount)
        {
            cnt++;
            dynamic row;
            if (rows.Current is NPOI.HSSF.UserModel.HSSFRow)
                row = (NPOI.HSSF.UserModel.HSSFRow) rows.Current;
            else
                row = (NPOI.XSSF.UserModel.XSSFRow) rows.Current;

            DataRow dr = dt.NewRow();

            for (int i = 0; i < row.LastCellNum; i++)
            {
                ICell cell = row.GetCell(i);

                if (cell == null)
                {
                    dr[i - 1] = null;
                }
                else if (i > 0)
                {
                    switch (cell.CellType)
                    {
                        case CellType.Blank:
                            dr[i - 1] = "[null]";
                            break;
                        case CellType.Boolean:
                            dr[i - 1] = cell.BooleanCellValue;
                            break;
                        case CellType.Numeric:
                            dr[i - 1] = cell.ToString();
                            break;
                        case CellType.String:
                            dr[i - 1] = cell.StringCellValue;
                            break;
                        case CellType.Error:
                            dr[i - 1] = cell.ErrorCellValue;
                            break;
                        case CellType.Formula:
                        default:
                            dr[i - 1] = "=" + cell.CellFormula;
                            break;
                    }
                }
            }
            dt.Rows.Add(dr);
        }
        return dt;
    }

Answer 2

你能发布一些你的服务器的规格吗？是否有机会基于 VM 和云？在过去，我成功地使用了：

1. Koogra : https://sourceforge.net/projects/koogra/

2. NPOI : http://npoi.codeplex.com/

   要读取 .xls 文件，但如果您可以将文件限制为 .xlsx，我将使用 ClosedXML。我已经在 Azure 中强大的 VM 上使用 ClosedXML 读取了大量 50K+ 的大文件，没有问题。我有一种感觉，您正在撞到服务器上的用户空间墙。如果用户达到这样的百分比，他们就会达到他们的使用配额并结束任务。