// ------------------------- LoadDocumentViewer -----------------------
/// <summary>
///   Loads content from a file to a DocumentViewer control.</summary>
/// <param name="xpsFilename">
///   The path and name of the XPS file to
///   load to the DocumentViewer control.</param>
/// <remarks>
///   Exception handling should be added if the xpsFilename may not be
///   valid or if the FixedDocumentSequence contained in the file is
///   incorrect.  (In this sample the files are hardcoded.)</remarks>
private void LoadDocumentViewer(string xpsFilename)
{
    // Save a reference to the currently open XPS package.
    XpsDocument oldXpsPackage = _xpsPackage;

    // Open the package for the new XPS document.
    _xpsPackage = new XpsDocument(xpsFilename,
        FileAccess.Read, CompressionOption.NotCompressed);

    // Get the FixedDocumentSequence from the package.
    FixedDocumentSequence fixedDocumentSequence =
        _xpsPackage.GetFixedDocumentSequence();

    // Set the new FixedDocumentSequence as
    // the DocumentViewer's paginator source.
    docViewer.Document =
        fixedDocumentSequence as IDocumentPaginatorSource;

    // If there was an old XPS package, close it now that
    // DocumentViewer no longer needs to access it.
    if (oldXpsPackage != null)
        oldXpsPackage.Close();

    // Leave the new _xpsPackage open for DocumentViewer
    // to access additional required resources.
}// end:LoadDocumentViewer()