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Open a spreadsheet document for read-only access

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This topic shows how to use the classes in the Open XML SDK for Office to open a spreadsheet document for read-only access programmatically.

When to Open a Document for Read-Only Access

Sometimes you want to open a document to inspect or retrieve some information, and you want to do this in a way that ensures the document remains unchanged. In these instances, you want to open the document for read-only access. This How To topic discusses several ways to programmatically open a read-only spreadsheet document.

Getting a SpreadsheetDocument Object

In the Open XML SDK, the SpreadsheetDocument class represents an Excel document package. To create an Excel document, you create an instance of the SpreadsheetDocument class and populate it with parts. At a minimum, the document must have a workbook part that serves as a container for the document, and at least one worksheet part. The text is represented in the package as XML using SpreadsheetML markup.

To create the class instance from the document that you call one of the Open() overload methods. Several Open methods are provided, each with a different signature. The methods that let you specify whether a document is editable are listed in the following table.

Open Class Library Reference Topic Description
Open(String, Boolean) Open(String, Boolean) Create an instance of the SpreadsheetDocument class from the specified file.
Open(Stream, Boolean) Open(Stream, Boolean Create an instance of the SpreadsheetDocument class from the specified IO stream.
Open(String, Boolean, OpenSettings) Open(String, Boolean, OpenSettings) Create an instance of the SpreadsheetDocument class from the specified file.
Open(Stream, Boolean, OpenSettings) Open(Stream, Boolean, OpenSettings) Create an instance of the SpreadsheetDocument class from the specified I/O stream.

The table earlier in this topic lists only those Open methods that accept a Boolean value as the second parameter to specify whether a document is editable. To open a document for read-only access, specify False for this parameter.

Notice that two of the Open methods create an instance of the SpreadsheetDocument class based on a string as the first parameter. The first example in the sample code uses this technique. It uses the first Open method in the table earlier in this topic; with a signature that requires two parameters. The first parameter takes a string that represents the full path file name from which you want to open the document. The second parameter is either true or false. This example uses false and indicates that you want to open the file as read-only.

The following code example calls the Open Method.

// Open a SpreadsheetDocument based on a file path.
using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(filePath, false))

The other two Open methods create an instance of the SpreadsheetDocument class based on an input/output stream. You might use this approach, for example, if you have a Microsoft SharePoint Foundation 2010 application that uses stream input/output, and you want to use the Open XML SDK to work with a document.

The following code example opens a document based on a stream.

// Open a SpreadsheetDocument based on a stream.
Stream stream = File.Open(filePath, FileMode.Open);

using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(stream, false))

Suppose you have an application that uses the Open XML support in the System.IO.Packaging namespace of the .NET Framework Class Library, and you want to use the Open XML SDK to work with a package as read-only. Whereas the Open XML SDK includes method overloads that accept a Package as the first parameter, there is not one that takes a Boolean as the second parameter to indicate whether the document should be opened for editing.

The recommended method is to open the package as read-only at first, before creating the instance of the SpreadsheetDocument class, as shown in the second example in the sample code. The following code example performs this operation.

// Open System.IO.Packaging.Package.
Package spreadsheetPackage = Package.Open(filePath, FileMode.Open, FileAccess.Read);

// Open a SpreadsheetDocument based on a package.
using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(spreadsheetPackage))

Basic Document Structure

The basic document structure of a SpreadsheetML document consists of the Sheets and Sheet elements, which reference the worksheets in the Workbook. A separate XML file is created for each Worksheet. For example, the SpreadsheetML for a workbook that has two worksheets name MySheet1 and MySheet2 is located in the Workbook.xml file and is as follows.

    <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> 
    <workbook xmlns=https://schemas.openxmlformats.org/spreadsheetml/2006/main xmlns:r="https://schemas.openxmlformats.org/officeDocument/2006/relationships">
        <sheets>
            <sheet name="MySheet1" sheetId="1" r:id="rId1" /> 
            <sheet name="MySheet2" sheetId="2" r:id="rId2" /> 
        </sheets>
    </workbook>

The worksheet XML files contain one or more block level elements such as SheetData. sheetData represents the cell table and contains one or more Row elements. A row contains one or more Cell elements. Each cell contains a CellValue element that represents the value of the cell. For example, the SpreadsheetML for the first worksheet in a workbook, that only has the value 100 in cell A1, is located in the Sheet1.xml file and is as follows.

    <?xml version="1.0" encoding="UTF-8" ?> 
    <worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
        <sheetData>
            <row r="1">
                <c r="A1">
                    <v>100</v> 
                </c>
            </row>
        </sheetData>
    </worksheet>

Using the Open XML SDK, you can create document structure and content that uses strongly-typed classes that correspond to SpreadsheetML elements. You can find these classes in the DocumentFormat.OpenXML.Spreadsheet namespace. The following table lists the class names of the classes that correspond to the workbook, sheets, sheet, worksheet, and sheetData elements.

SpreadsheetML Element Open XML SDK Class Description
workbook DocumentFormat.OpenXml.Spreadsheet.Workbook The root element for the main document part.
sheets DocumentFormat.OpenXml.Spreadsheet.Sheets The container for the block level structures such as sheet, fileVersion, and others specified in the ISO/IEC 29500 specification.
sheet DocumentFormat.OpenXml.Spreadsheet.Sheet A sheet that points to a sheet definition file.
worksheet DocumentFormat.OpenXml.Spreadsheet.Worksheet A sheet definition file that contains the sheet data.
sheetData DocumentFormat.OpenXml.Spreadsheet.SheetData The cell table, grouped together by rows.
row DocumentFormat.OpenXml.Spreadsheet.Row A row in the cell table.
c DocumentFormat.OpenXml.Spreadsheet.Cell A cell in a row.
v DocumentFormat.OpenXml.Spreadsheet.CellValue The value of a cell.

Sample Code

The following is the complete sample code in both C# and Visual Basic.

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

static void OpenSpreadsheetDocumentReadonly(string filePath)
{
    // Open a SpreadsheetDocument based on a file path.
    using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(filePath, false))
    {
        if (spreadsheetDocument.WorkbookPart is not null)
        {
            // Attempt to add a new WorksheetPart.
            // The call to AddNewPart generates an exception because the file is read-only.
            WorksheetPart newWorksheetPart = spreadsheetDocument.WorkbookPart.AddNewPart<WorksheetPart>();

            // The rest of the code will not be called.
        }
    }

    // Open a SpreadsheetDocument based on a stream.
    Stream stream = File.Open(filePath, FileMode.Open);

    using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(stream, false))
    {
        if (spreadsheetDocument.WorkbookPart is not null)
        {
            // Attempt to add a new WorksheetPart.
            // The call to AddNewPart generates an exception because the file is read-only.
            WorksheetPart newWorksheetPart = spreadsheetDocument.WorkbookPart.AddNewPart<WorksheetPart>();

            // The rest of the code will not be called.
        }
    }

    // Open System.IO.Packaging.Package.
    Package spreadsheetPackage = Package.Open(filePath, FileMode.Open, FileAccess.Read);

    // Open a SpreadsheetDocument based on a package.
    using (SpreadsheetDocument spreadsheetDocument = SpreadsheetDocument.Open(spreadsheetPackage))
    {
        if (spreadsheetDocument.WorkbookPart is not null)
        {
            // Attempt to add a new WorksheetPart.
            // The call to AddNewPart generates an exception because the file is read-only.
            WorksheetPart newWorksheetPart = spreadsheetDocument.WorkbookPart.AddNewPart<WorksheetPart>();

            // The rest of the code will not be called.
        }
    }
}

See also