Using OpenXmlReader

问题:

I hate to resort to StackOverflow for something so (seemingly) basic, but I've been fighting with Microsoft for the last few hours and seem to be hitting a dead end. I am trying to read (large) Excel 2007+ spreadsheets, and Google has kindly informed me that using the OpenXml SDK is a pretty popular choice. So I gave the thing a shot, read some tutorials, checked Microsoft's own library pages, and got very little out of them all.

I am using a small test spreadsheet with just one column of numbers and one of strings - large scale testing will come later. I've tried several implementations similar to the one I am about to post, and none of them read data. The code below was mostly taken from another StackOverflow thread, where it seemed to have worked - not so for me. I figured I'll have you guys check/debug/help with this version, because it'll likely be less broken than anything I have written today.

static void ReadExcelFileSAX(string fileName)
    {
        using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(fileName, true))
        {
            WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;
            WorksheetPart worksheetPart = workbookPart.WorksheetParts.First();

            OpenXmlPartReader reader = new OpenXmlPartReader(worksheetPart);
            string text;
            string rowNum;
            while (reader.Read())
            {
                if (reader.ElementType == typeof(Row))
                {
                    do
                    {
                        if (reader.HasAttributes)
                        {
                            rowNum = reader.Attributes.First(a => a.LocalName == "r").Value;
                            Console.Write("rowNum: " + rowNum); //we never even get here, I tested it with a breakpoint
                        }

                    } while (reader.ReadNextSibling()); // Skip to the next row
                    Console.ReadKey();
                    break; // We just looped through all the rows so no need to continue reading the worksheet
                }
                if (reader.ElementType == typeof(Cell))
                {

                }

                if (reader.ElementType != typeof(Worksheet)) // Dont' want to skip the contents of the worksheet
                    reader.Skip(); // Skip contents of any node before finding the first row.
            }
            reader.Close();
            Console.WriteLine();
            Console.ReadKey();
        }
    }

And, on a side note, are there any good alternatives to using the OpenXml SDK I have somehow missed?

回答1:

I think you took the wrong WorksheetPart for reading the rows.

The line

workbookPart.WorksheetParts.First();

gets the first WorksheetPart of the collection which must not necessarily be the first worksheet as you see it in Microsoft Excel.

So, iterate through all WorksheetParts and you should see some output on your console window.

static void ReadExcelFileSAX(string fileName)
{
  using (SpreadsheetDocument spreadsheetDocument = 
                                   SpreadsheetDocument.Open(fileName, true))
  {
    WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;

    // Iterate through all WorksheetParts
    foreach (WorksheetPart worksheetPart in workbookPart.WorksheetParts)
    {          
      OpenXmlPartReader reader = new OpenXmlPartReader(worksheetPart);
      string text;
      string rowNum;
      while (reader.Read())
      {
        if (reader.ElementType == typeof(Row))
        {
          do
          {
            if (reader.HasAttributes)
            {
              rowNum = reader.Attributes.First(a => a.LocalName == "r").Value;
              Console.Write("rowNum: " + rowNum);
            }

          } while (reader.ReadNextSibling()); // Skip to the next row

          break; // We just looped through all the rows so no 
                 // need to continue reading the worksheet
        }

        if (reader.ElementType != typeof(Worksheet))
          reader.Skip(); 
      }
      reader.Close();      
    }
  }  
}

To read all cell values use the following function (all error handling details omitted) :

static void ReadAllCellValues(string fileName)
{
  using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(fileName, false))
  {
    WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;

    foreach(WorksheetPart worksheetPart in workbookPart.WorksheetParts)
    {
      OpenXmlReader reader = OpenXmlReader.Create(worksheetPart);

      while (reader.Read())
      {
        if (reader.ElementType == typeof(Row))
        {
          reader.ReadFirstChild();

          do
          {
            if (reader.ElementType == typeof(Cell))
            {
              Cell c = (Cell)reader.LoadCurrentElement();

              string cellValue;

              if (c.DataType != null && c.DataType == CellValues.SharedString)
              {
                SharedStringItem ssi = workbookPart.SharedStringTablePart.SharedStringTable.Elements<SharedStringItem>().ElementAt(int.Parse(c.CellValue.InnerText));

                cellValue = ssi.Text.Text;
              }
              else
              {
                cellValue = c.CellValue.InnerText;
              }

              Console.Out.Write("{0}: {1} ", c.CellReference, cellValue);
            }
          } while (reader.ReadNextSibling());
          Console.Out.WriteLine();
        }            
      }
    }   
  }
}

In the code above you see that cells with data type SharedString must be handled using the SharedStringTablePart.

回答2:

To read blank cells, I am using a variable assigned outside the row reader and in while loop, I am checking if column index is greater than or not from my variable as it is being incremented after each cell read. if this does not match, I am filling my column with value I want to. This is the trick I used to catch up the blank cells into my respecting column value. Here is the code:

public static DataTable ReadIntoDatatableFromExcel(string newFilePath)
        {
            /*Creating a table with 20 columns*/
            var dt = CreateProviderRvenueSharingTable();

            try
            {
                /*using stream so that if excel file is in another process then it can read without error*/
                using (Stream stream = new FileStream(newFilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
                {
                    using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(stream, false))
                    {
                        var workbookPart = spreadsheetDocument.WorkbookPart;
                        var workbook = workbookPart.Workbook;

                        /*get only unhide tabs*/
                        var sheets = workbook.Descendants<Sheet>().Where(e => e.State == null);

                        foreach (var sheet in sheets)
                        {
                            var worksheetPart = (WorksheetPart)workbookPart.GetPartById(sheet.Id);

                            /*Remove empty sheets*/
                            List<Row> rows = worksheetPart.Worksheet.Elements<SheetData>().First().Elements<Row>()
                                .Where(r => r.InnerText != string.Empty).ToList();

                            if (rows.Count > 1)
                            {
                                OpenXmlReader reader = OpenXmlReader.Create(worksheetPart);

                                int i = 0;
                                int BTR = 0;/*Break the reader while empty rows are found*/

                                while (reader.Read())
                                {
                                    if (reader.ElementType == typeof(Row))
                                    {
                                        /*ignoring first row with headers and check if data is there after header*/
                                        if (i < 2)
                                        {
                                            i++;
                                            continue;
                                        }

                                        reader.ReadFirstChild();

                                        DataRow row = dt.NewRow();

                                        int CN = 0;

                                        if (reader.ElementType == typeof(Cell))
                                        {
                                            do
                                            {
                                                Cell c = (Cell)reader.LoadCurrentElement();

                                                /*reader skipping blank cells so data is getting worng in datatable's rows according to header*/
                                                if (CN != 0)
                                                {
                                                    int cellColumnIndex =
                                                        ExcelHelper.GetColumnIndexFromName(
                                                            ExcelHelper.GetColumnName(c.CellReference));

                                                    if (cellColumnIndex < 20 && CN < cellColumnIndex - 1)
                                                    {
                                                        do
                                                        {
                                                            row[CN] = string.Empty;
                                                            CN++;
                                                        } while (CN < cellColumnIndex - 1);
                                                    }
                                                }

                                                /*stopping execution if first cell does not have any value which means empty row*/
                                                if (CN == 0 && c.DataType == null && c.CellValue == null)
                                                {
                                                    BTR++;
                                                    break;
                                                }

                                                string cellValue = GetCellValue(c, workbookPart);
                                                row[CN] = cellValue;
                                                CN++;

                                                /*if any text exists after T column (index 20) then skip the reader*/
                                                if (CN == 20)
                                                {
                                                    break;
                                                }
                                            } while (reader.ReadNextSibling());
                                        }

                                        /*reader skipping blank cells so fill the array upto 19 index*/
                                        while (CN != 0 && CN < 20)
                                        {
                                            row[CN] = string.Empty;
                                            CN++;
                                        }

                                        if (CN == 20)
                                        {
                                            dt.Rows.Add(row);
                                        }
                                    }
                                    /*escaping empty rows below data filled rows after checking 5 times */
                                    if (BTR > 5)
                                        break;
                                }
                                reader.Close();
                            }                            
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            return dt;
        }

  private static string GetCellValue(Cell c, WorkbookPart workbookPart)
        {
            string cellValue = string.Empty;
            if (c.DataType != null && c.DataType == CellValues.SharedString)
            {
                SharedStringItem ssi =
                    workbookPart.SharedStringTablePart.SharedStringTable
                        .Elements<SharedStringItem>()
                        .ElementAt(int.Parse(c.CellValue.InnerText));
                if (ssi.Text != null)
                {
                    cellValue = ssi.Text.Text;
                }
            }
            else
            {
                if (c.CellValue != null)
                {
                    cellValue = c.CellValue.InnerText;
                }
            }
            return cellValue;
        }

public static int GetColumnIndexFromName(string columnNameOrCellReference)
        {
            int columnIndex = 0;
            int factor = 1;
            for (int pos = columnNameOrCellReference.Length - 1; pos >= 0; pos--)   // R to L
            {
                if (Char.IsLetter(columnNameOrCellReference[pos]))  // for letters (columnName)
                {
                    columnIndex += factor * ((columnNameOrCellReference[pos] - 'A') + 1);
                    factor *= 26;
                }
            }
            return columnIndex;
        }

        public static string GetColumnName(string cellReference)
        {
            /* Advance from L to R until a number, then return 0 through previous position*/
            for (int lastCharPos = 0; lastCharPos <= 3; lastCharPos++)
                if (Char.IsNumber(cellReference[lastCharPos]))
                    return cellReference.Substring(0, lastCharPos);

            throw new ArgumentOutOfRangeException("cellReference");
        }

Code works for: 1. This code reads blank cells 2. skip empty rows after reading complete. 3. read the sheet from first in ascending order 4. if excel file is being used by another process, OpenXML still reads that.