Export DataTable to Excel with Open Xml SDK in c#

Question

My program have ability to export some data and DataTable to Excel file (template) In the template I insert the data to some placeholders. It's works very good, but I need to insert a DataTable too... My sample code:

using (Stream OutStream = new MemoryStream())
{
    // read teamplate
    using (var fileStream = File.OpenRead(templatePath))
        fileStream.CopyTo(OutStream);

    // exporting
    Exporting(OutStream);
         
    // to start
    OutStream.Seek(0L, SeekOrigin.Begin);
            
    // out
    using (var resultFile = File.Create(resultPath))
        OutStream.CopyTo(resultFile);

Next method to exporting

private void Exporting(Stream template)
{
    using (var workbook = SpreadsheetDocument.Open(template, true, new OpenSettings                          { AutoSave = true }))
    {
        // Replace shared strings
        SharedStringTablePart sharedStringsPart = workbook.WorkbookPart.SharedStringTablePart;
        IEnumerable<Text> sharedStringTextElements = sharedStringsPart.SharedStringTable.Descendants<Text>();
           
        DoReplace(sharedStringTextElements);
        // Replace inline strings
        IEnumerable<WorksheetPart> worksheetParts = workbook.GetPartsOfType<WorksheetPart>();
          
        foreach (var worksheet in worksheetParts)
        {
            DoReplace(worksheet.Worksheet.Descendants<Text>());
        }

        int z = 40;
        foreach (System.Data.DataRow row in ExcelWorkXLSX.ToOut.Rows)
        {
            for (int i = 0; i < row.ItemArray.Count(); i++)
            { 
                ExcelWorkXLSX.InsertText(workbook, row.ItemArray.ElementAt(i).ToString(), getColumnName(i), Convert.ToUInt32(z)); }
                z++;
            }
        } 
        
    }
}

But this fragment to output DataTable slooooooooooooooooooooooowwwwwww...

How can I export DataTable to Excel fast and truly?

Answer 1

I wrote this quick example. It works for me. I only tested it with one dataset with one table inside, but I guess that may be enough for you.

Take into consideration that I treated all cells as String (not even SharedStrings). If you want to use SharedStrings you might need to tweak my sample a bit.

Edit: To make this work it is necessary to add WindowsBase and DocumentFormat.OpenXml references to project.

Enjoy,

private void ExportDataSet(DataSet ds, string destination)
        {
            using (var workbook = SpreadsheetDocument.Create(destination, DocumentFormat.OpenXml.SpreadsheetDocumentType.Workbook))
            {
                var workbookPart = workbook.AddWorkbookPart();

                workbook.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();

                workbook.WorkbookPart.Workbook.Sheets = new DocumentFormat.OpenXml.Spreadsheet.Sheets();

                foreach (System.Data.DataTable table in ds.Tables) {

                    var sheetPart = workbook.WorkbookPart.AddNewPart<WorksheetPart>();
                    var sheetData = new DocumentFormat.OpenXml.Spreadsheet.SheetData();
                    sheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(sheetData);

                    DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = workbook.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>();
                    string relationshipId = workbook.WorkbookPart.GetIdOfPart(sheetPart);

                    uint sheetId = 1;
                    if (sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Count() > 0)
                    {
                        sheetId =
                            sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Select(s => s.SheetId.Value).Max() + 1;
                    }

                    DocumentFormat.OpenXml.Spreadsheet.Sheet sheet = new DocumentFormat.OpenXml.Spreadsheet.Sheet() { Id = relationshipId, SheetId = sheetId, Name = table.TableName };
                    sheets.Append(sheet);

                    DocumentFormat.OpenXml.Spreadsheet.Row headerRow = new DocumentFormat.OpenXml.Spreadsheet.Row();

                    List<String> columns = new List<string>();
                    foreach (System.Data.DataColumn column in table.Columns) {
                        columns.Add(column.ColumnName);

                        DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                        cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                        cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(column.ColumnName);
                        headerRow.AppendChild(cell);
                    }


                    sheetData.AppendChild(headerRow);

                    foreach (System.Data.DataRow dsrow in table.Rows)
                    {
                        DocumentFormat.OpenXml.Spreadsheet.Row newRow = new DocumentFormat.OpenXml.Spreadsheet.Row();
                        foreach (String col in columns)
                        {
                            DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                            cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                            cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(dsrow[col].ToString()); //
                            newRow.AppendChild(cell);
                        }

                        sheetData.AppendChild(newRow);
                    }

                }
            }
        }

Answer 2

eburgos, I've modified your code slightly because when you have multiple datatables in your dataset it was just overwriting them in the spreadsheet so you were only left with one sheet in the workbook. I basically just moved the part where the workbook is created out of the loop. Here is the updated code.

private void ExportDSToExcel(DataSet ds, string destination)
{
    using (var workbook = SpreadsheetDocument.Create(destination, DocumentFormat.OpenXml.SpreadsheetDocumentType.Workbook))
    {
        var workbookPart = workbook.AddWorkbookPart();
        workbook.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();
        workbook.WorkbookPart.Workbook.Sheets = new DocumentFormat.OpenXml.Spreadsheet.Sheets();

        uint sheetId = 1;

        foreach (DataTable table in ds.Tables)
        {
            var sheetPart = workbook.WorkbookPart.AddNewPart<WorksheetPart>();
            var sheetData = new DocumentFormat.OpenXml.Spreadsheet.SheetData();
            sheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(sheetData);                

            DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = workbook.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>();
            string relationshipId = workbook.WorkbookPart.GetIdOfPart(sheetPart);

            if (sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Count() > 0)
            {
                sheetId =
                    sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Select(s => s.SheetId.Value).Max() + 1;
            }

            DocumentFormat.OpenXml.Spreadsheet.Sheet sheet = new DocumentFormat.OpenXml.Spreadsheet.Sheet() { Id = relationshipId, SheetId = sheetId, Name = table.TableName };
            sheets.Append(sheet);

            DocumentFormat.OpenXml.Spreadsheet.Row headerRow = new DocumentFormat.OpenXml.Spreadsheet.Row();

            List<String> columns = new List<string>();
            foreach (DataColumn column in table.Columns)
            {
                columns.Add(column.ColumnName);

                DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(column.ColumnName);
                headerRow.AppendChild(cell);
            }

            sheetData.AppendChild(headerRow);

            foreach (DataRow dsrow in table.Rows)
            {
                DocumentFormat.OpenXml.Spreadsheet.Row newRow = new DocumentFormat.OpenXml.Spreadsheet.Row();
                foreach (String col in columns)
                {
                    DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                    cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                    cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(dsrow[col].ToString()); //
                    newRow.AppendChild(cell);
                }

                sheetData.AppendChild(newRow);
            }
        }
    }
}

Answer 3

I also wrote a C#/VB.Net "Export to Excel" library, which uses OpenXML and (more importantly) also uses OpenXmlWriter, so you won't run out of memory when writing large files.

Full source code, and a demo, can be downloaded here:

Export to Excel

It's dead easy to use. Just pass it the filename you want to write to, and a DataTable, DataSet or List<>.

CreateExcelFile.CreateExcelDocument(myDataSet, "MyFilename.xlsx");

And if you're calling it from an ASP.Net application, pass it the HttpResponse to write the file out to.

CreateExcelFile.CreateExcelDocument(myDataSet, "MyFilename.xlsx", Response);

Answer 4

I wrote my own export to Excel writer because nothing else quite met my needs. It is fast and allows for substantial formatting of the cells. You can review it at

https://openxmlexporttoexcel.codeplex.com/

I hope it helps.