Structure of a SpreadsheetML document

using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;

CreateSpreadsheetWorkbook(args[0]);

static void CreateSpreadsheetWorkbook(string filepath)
{
    // Create a spreadsheet document by supplying the filepath.
    // By default, AutoSave = true, Editable = true, and Type = xlsx.
    SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Create(filepath, SpreadsheetDocumentType.Workbook);

    // Add a WorkbookPart to the document.
    WorkbookPart workbookPart = spreadsheetDocument.AddWorkbookPart();
    workbookPart.Workbook = new Workbook();

    // Add a WorksheetPart to the WorkbookPart.
    WorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>();
    worksheetPart.Worksheet = new Worksheet(new SheetData());

    // Add Sheets to the Workbook.
    Sheets sheets = workbookPart.Workbook.AppendChild(new Sheets());

    // Append a new worksheet and associate it with the workbook.
    Sheet sheet = new Sheet() { Id = workbookPart.GetIdOfPart(worksheetPart), SheetId = 1, Name = "mySheet" };
    sheets.Append(sheet);

    workbookPart.Workbook.Save();

    // Dispose the document.
    spreadsheetDocument.Dispose();
}

Imports DocumentFormat.OpenXml
Imports DocumentFormat.OpenXml.Packaging
Imports DocumentFormat.OpenXml.Spreadsheet

Module MyModule

    Sub Main(args As String())
    End Sub

    Public Sub CreateSpreadsheetWorkbook(ByVal filepath As String)
        ' Create a spreadsheet document by supplying the filepath.
        ' By default, AutoSave = true, Editable = true, and Type = xlsx.
        Dim spreadsheetDocument As SpreadsheetDocument = SpreadsheetDocument.Create(filepath, SpreadsheetDocumentType.Workbook)

        ' Add a WorkbookPart to the document.
        Dim workbookpart As WorkbookPart = spreadsheetDocument.AddWorkbookPart
        workbookpart.Workbook = New Workbook

        ' Add a WorksheetPart to the WorkbookPart.
        Dim worksheetPart As WorksheetPart = workbookpart.AddNewPart(Of WorksheetPart)()
        worksheetPart.Worksheet = New Worksheet(New SheetData())

        ' Add Sheets to the Workbook.
        Dim sheets As Sheets = spreadsheetDocument.WorkbookPart.Workbook.AppendChild(Of Sheets)(New Sheets())

        ' Append a new worksheet and associate it with the workbook.
        Dim sheet As Sheet = New Sheet
        sheet.Id = spreadsheetDocument.WorkbookPart.GetIdOfPart(worksheetPart)
        sheet.SheetId = 1
        sheet.Name = "mySheet"

        sheets.Append(sheet)

        workbookpart.Workbook.Save()

        ' Dispose the document.
        spreadsheetDocument.Dispose()
    End Sub
End Module

Generated SpreadsheetML

After you run the Open XML SDK code to generate a minimum workbook, you can explore the contents of the .zip package to view the SpreadsheetML XML code. To view the .zip package, rename the extension on the minimum spreadsheet from .xlsx to .zip. Inside the .zip package, there are several parts that make up the minimum workbook.

The following figure shows the structure under the xl folder of the .zip package for a minimum workbook.

Figure 1. .zip folder structure

The workbook.xml file contains <sheet> elements that reference the worksheets in the workbook. Each worksheet is associated to the workbook via a Sheet ID and a relationship ID. The sheetID is the ID used within the package to identify a sheet and must be unique within the workbook. The id is the relationship ID that identifies the sheet part definition associated with a sheet.

The following XML code is the spreadsheetML that represents the workbook part of the spreadsheet document. This code is generated when you run the Open XML SDK code to create a minimum workbook.

    <?xml version="1.0" encoding="utf-8"?>
    <x:workbook xmlns:x="https://schemas.openxmlformats.org/spreadsheetml/2006/main">
        <x:sheets>
            <x:sheet name="mySheet" sheetId="1" r:id="Rddc7711f116045e5" xmlns:r="https://schemas.openxmlformats.org/officeDocument/2006/relationships" />
        </x:sheets>
    </x:workbook>

The workbook.xml.rels file contains the <Relationship> elements that define the relationships between the workbook and the worksheets it contains.

The following XML code is the spreadsheetML that represents the relationship part of the spreadsheet document. This code is generated when you run the Open XML SDK to create a minimum workbook.

    <?xml version="1.0" encoding="utf-8"?>
    <Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
        <Relationship Type="https://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="/xl/worksheets/sheet.xml" Id="Rddc7711f116045e5" />
    </Relationships>

The sheet.xml file contains the <sheetData> element that represents the cell table. In this example, the workbook is blank, so the <sheetData> element is empty. For more information about sheets, see Working with sheets**.

The following XML code is the spreadsheetML that represents the worksheet part of the spreadsheet document. This code is generated when you run the Open XML SDK to create a minimum workbook.

    <?xml version="1.0" encoding="utf-8"?>
    <x:worksheet xmlns:x="https://schemas.openxmlformats.org/spreadsheetml/2006/main">
        <x:sheetData />
    </x:worksheet>