How can I write to an Excel spreadsheet using Linq?

Question

I\'m writing an app where I need to retrieve some rows from a DB and dump them into an Excel spreadsheet. I\'m using Linq to retrieve these rows.

Is it possible to

Answer 1

You can:

• Create a CSV file, which is associated with Excel on most systems.
• Create Excel Worksheet object and populate it manually. Google Search
• Using an XLS/XLSX generating Control. I have use Spire.XLS from http://www.e-iceblue.com/xls/xlsintro.htm

Answer 2

Take a look at this Excel Data Object Provider. I haven't personally used the writing functionality of it and I adapted the reading support to allow for ordinal (as well as named) column identifiers, but it may be a step in the right direction. Keep in mind that you cannot write or read from XLSX files unless Excel 2003+ is installed on the target machine; standard XLS files will work on any Windows box though.

My adapted version with ordinal columns can be found here. You may find it necessary/helpful to implement that in the current version (at the above link) if you decide to use the code. My version is a hybrid of features from the version 2.0 and 2.5- it has all of the reading functionality (with some 2.5 upgrades), but no writing. Oh- and unlike either version 2.0 or 2.5, my version doesn't require that the first sheet in the Excel document be named "Sheet1".

Hope that helps!

Answer 3

There's no direct way to connect these two. It sounds like you want LINQ to SQL to handle the query generation, but not the O/R mapping (because Excel wouldn't know what to do with the objects that come out of LINQ- they don't look like data rows any more). You can do that first part by calling (datacontext).GetCommand(yourLinqQueryHere), then running that as the CommandText in a SqlCommand. Call ExecuteReader(), then GetSchemaTable() to figure out the order of the columns. Then (assuming you're automating Excel) pass the result of (DbDataReader).GetValues() to Excel's (Worksheet).Row[x].Values and it'll splat the results in. You might need to reorder stuff. If you're not automating Excel, you'd need to dump the values in using the Jet OLEDB provider for Excel with an OleDbConnection, or use a 3rd party component to generate the spreadsheet.

Answer 4

I am personally not a big fan of using libraries to such things as I always find it limiting at some point later...

I used reflection in order to generate the column headers and get the cell values of each row. And if you are using .NET framework 3.5 your can take advantage of extensions methods so that you can export any IEnumerable<object> to an excel XDocument file.

Here is how I did it:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace YourNameSpace
{
    public static class ExcelExportExtensions
    {
        public static XDocument ToExcelXml(this IEnumerable<object> rows)
        {
            return rows.ToExcelXml("Sheet1");
        }

        public static XDocument ToExcelXml(this IEnumerable<object> rows, string sheetName)
        {
            sheetName = sheetName.Replace("/", "-");
            sheetName = sheetName.Replace("\\", "-");

            XNamespace mainNamespace = "urn:schemas-microsoft-com:office:spreadsheet";
            XNamespace o = "urn:schemas-microsoft-com:office:office";
            XNamespace x = "urn:schemas-microsoft-com:office:excel";
            XNamespace ss = "urn:schemas-microsoft-com:office:spreadsheet";
            XNamespace html = "http://www.w3.org/TR/REC-html40";

            XDocument xdoc = new XDocument(new XDeclaration("1.0", "utf-8", "yes"));

            var headerRow = from p in rows.First().GetType().GetProperties()
                            select new XElement(mainNamespace + "Cell",
                                new XElement(mainNamespace + "Data",
                                    new XAttribute(ss + "Type", "String"), p.Name)); //Generate header using reflection

            XElement workbook = new XElement(mainNamespace + "Workbook",
                new XAttribute(XNamespace.Xmlns + "html", html),
                new XAttribute(XName.Get("ss", "http://www.w3.org/2000/xmlns/"), ss),
                new XAttribute(XName.Get("o", "http://www.w3.org/2000/xmlns/"), o),
                new XAttribute(XName.Get("x", "http://www.w3.org/2000/xmlns/"), x),
                new XAttribute(XName.Get("xmlns", ""), mainNamespace),
                new XElement(o + "DocumentProperties",
                        new XAttribute(XName.Get("xmlns", ""), o),
                        new XElement(o + "Author", "Smartdesk Systems Ltd"),
                        new XElement(o + "LastAuthor", "Smartdesk Systems Ltd"),
                        new XElement(o + "Created", DateTime.Now.ToString())
                    ), //end document properties
                new XElement(x + "ExcelWorkbook",
                        new XAttribute(XName.Get("xmlns", ""), x),
                        new XElement(x + "WindowHeight", 12750),
                        new XElement(x + "WindowWidth", 24855),
                        new XElement(x + "WindowTopX", 240),
                        new XElement(x + "WindowTopY", 75),
                        new XElement(x + "ProtectStructure", "False"),
                        new XElement(x + "ProtectWindows", "False")
                    ), //end ExcelWorkbook
                new XElement(mainNamespace + "Styles",
                        new XElement(mainNamespace + "Style",
                            new XAttribute(ss + "ID", "Default"),
                            new XAttribute(ss + "Name", "Normal"),
                            new XElement(mainNamespace + "Alignment",
                                new XAttribute(ss + "Vertical", "Bottom")
                            ),
                            new XElement(mainNamespace + "Borders"),
                            new XElement(mainNamespace + "Font",
                                new XAttribute(ss + "FontName", "Calibri"),
                                new XAttribute(x + "Family", "Swiss"),
                                new XAttribute(ss + "Size", "11"),
                                new XAttribute(ss + "Color", "#000000")
                            ),
                            new XElement(mainNamespace + "Interior"),
                            new XElement(mainNamespace + "NumberFormat"),
                            new XElement(mainNamespace + "Protection")
                        ),
                        new XElement(mainNamespace + "Style",
                            new XAttribute(ss + "ID", "Header"),
                            new XElement(mainNamespace + "Font",
                                new XAttribute(ss + "FontName", "Calibri"),
                                new XAttribute(x + "Family", "Swiss"),
                                new XAttribute(ss + "Size", "11"),
                                new XAttribute(ss + "Color", "#000000"),
                                new XAttribute(ss + "Bold", "1")
                            )
                        )
                    ), // close styles
                    new XElement(mainNamespace + "Worksheet",
                        new XAttribute(ss + "Name", sheetName /* Sheet name */),
                        new XElement(mainNamespace + "Table",
                            new XAttribute(ss + "ExpandedColumnCount", headerRow.Count()),
                            new XAttribute(ss + "ExpandedRowCount", rows.Count() + 1),
                            new XAttribute(x + "FullColumns", 1),
                            new XAttribute(x + "FullRows", 1),
                            new XAttribute(ss + "DefaultRowHeight", 15),
                            new XElement(mainNamespace + "Column",
                                new XAttribute(ss + "Width", 81)
                            ),
                            new XElement(mainNamespace + "Row", new XAttribute(ss + "StyleID", "Header"), headerRow),
                            from contentRow in rows
                            select new XElement(mainNamespace + "Row",
                                new XAttribute(ss + "StyleID", "Default"),
                                    from p in contentRow.GetType().GetProperties()
                                    select new XElement(mainNamespace + "Cell",
                                         new XElement(mainNamespace + "Data", new XAttribute(ss + "Type", "String"), p.GetValue(contentRow, null))) /* Build cells using reflection */ )
                        ), //close table
                        new XElement(x + "WorksheetOptions",
                            new XAttribute(XName.Get("xmlns", ""), x),
                            new XElement(x + "PageSetup",
                                new XElement(x + "Header",
                                    new XAttribute(x + "Margin", "0.3")
                                ),
                                new XElement(x + "Footer",
                                    new XAttribute(x + "Margin", "0.3")
                                ),
                                new XElement(x + "PageMargins",
                                    new XAttribute(x + "Bottom", "0.75"),
                                    new XAttribute(x + "Left", "0.7"),
                                    new XAttribute(x + "Right", "0.7"),
                                    new XAttribute(x + "Top", "0.75")
                                )
                            ),
                            new XElement(x + "Print",
                                new XElement(x + "ValidPrinterInfo"),
                                new XElement(x + "HorizontalResolution", 600),
                                new XElement(x + "VerticalResolution", 600)
                            ),
                            new XElement(x + "Selected"),
                            new XElement(x + "Panes",
                                new XElement(x + "Pane",
                                    new XElement(x + "Number", 3),
                                    new XElement(x + "ActiveRow", 1),
                                    new XElement(x + "ActiveCol", 0)
                                )
                            ),
                            new XElement(x + "ProtectObjects", "False"),
                            new XElement(x + "ProtectScenarios", "False")
                        ) // close worksheet options
                    ) // close Worksheet
                );

            xdoc.Add(workbook);

            return xdoc;
        }
    }
}

I have also created another extention method to ease return the XDocument in web scenarios:

public static DownloadableFile ToDownloadableXmlFileForExcel2003(this System.Xml.Linq.XDocument file, string fileName)
{
    MemoryStream ms = new MemoryStream();

    XmlWriterSettings xmlWriterSettings = new XmlWriterSettings() { Encoding = Encoding.UTF8 };
    XmlWriter xmlWriter = XmlWriter.Create(ms, xmlWriterSettings);

    file.Save(xmlWriter);   //.Save() adds the <xml /> header tag!
    xmlWriter.Close();      //Must close the writer to dump it's content its output (the memory stream)

    DownloadableFile dbf = 
            new DownloadableFile
            {
                FileName = String.Format("{0}.xls", fileName.Replace(" ", "")),
                Content  = ms.ToArray(),
                MimeType = "application/vnd.ms-excel"
            };

    ms.Close();
    ms.Dispose();

    return dbf;
}

Hope this helps!

Answer 5

The quickest solution will be to create a csv file:

col1, colb, colc
col1, colb, colc

Excel works very well with csv files.

Answer 6

The fact that you're retrieving your data with LINQ is sort of irrelevant. What you're really after is a good library to write Excel. Once you've got that, you can simply iterate through your results to create rows in your Excel worksheet.

As far as a library I've used NPOI, and it's been great.