how to create and download excel document using asp.net

just set Response.ContentType = "application/vnd.ms-excel" and your page will rendered as an excel sheet on the clients browser

Sample code here

Starter kit

First i have downloaded the Open XML Format SDK 2.0.

It comes with 3 useful tools in :

C:\Program Files\Open XML Format SDK\V2.0\tools

• DocumentReflector.exe wich auto generate the c# to build a spreadsheet from the code.
• OpenXmlClassesExplorer.exe display Ecma specification and the class documentation (using an MSDN style format).
• OpenXmlDiff.exe graphically compare two Open XML files and search for errors.

I suggest anyone who begin to rename .xlsx to .zip, so you can see the XML files who drive our spreadsheet ( for the example our sheets are in "xl\worksheets" ).

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The code

Disclaimer : I have stolen all the code from an MSDN technical article ;D

The following code use an *.xlsx template i made manually to be able to modify it.

Namespaces references

using System.IO;
using System.Xml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
using DocumentFormat.OpenXml;


// Database object
        DataClassesDataContext db = new DataClassesDataContext();

        // Make a copy of the template file.
        File.Copy(@"C:\inetpub\wwwroot\project.Web\Clients\Handlers\oxml-tpl\livreurs.xlsx", @"C:\inetpub\wwwroot\project.Web\Clients\Handlers\oxml-tpl\generated.xlsx", true);

        // Open the copied template workbook. 
        using (SpreadsheetDocument myWorkbook = SpreadsheetDocument.Open(@"C:\inetpub\wwwroot\project.Web\Clients\Handlers\oxml-tpl\generated.xlsx", true))
        {
            // Access the main Workbook part, which contains all references.
            WorkbookPart workbookPart = myWorkbook.WorkbookPart;

            // Get the first worksheet. 
            WorksheetPart worksheetPart = workbookPart.WorksheetParts.ElementAt(2);

            // The SheetData object will contain all the data.
            SheetData sheetData = worksheetPart.Worksheet.GetFirstChild<SheetData>();

            // Begining Row pointer                       
            int index = 2;

            // Database results
            var query = from t in db.Clients select t;

            // For each item in the database, add a Row to SheetData.
            foreach (var item in query)
            {
                // Cell related variable
                string Nom = item.Nom;

                // New Row
                Row row = new Row();
                row.RowIndex = (UInt32)index;

                // New Cell
                Cell cell = new Cell();
                cell.DataType = CellValues.InlineString;
                // Column A1, 2, 3 ... and so on
                cell.CellReference = "A"+index;

                // Create Text object
                Text t = new Text();
                t.Text = Nom;

                // Append Text to InlineString object
                InlineString inlineString = new InlineString();
                inlineString.AppendChild(t);

                // Append InlineString to Cell
                cell.AppendChild(inlineString);

                // Append Cell to Row
                row.AppendChild(cell);

                // Append Row to SheetData
                sheetData.AppendChild(row);

                // increase row pointer
                index++;                

            }

            // save
            worksheetPart.Worksheet.Save();

        }

I havent finished yet, my second job is to auto download the spreadsheet after modification.

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Finally, i redirect the user to my generated spredsheet (from my aspx)

 context.Response.Redirect("Oxml-tpl/generated.xlsx");