PageIndexFilter

AsposeWordsPrintDocument.PageIndexFilter property

Gets or sets the zero-based index filter used to determine which pages to skip during printing.

public IIndexFilter PageIndexFilter { get; set; }

Remarks

Please note that if some pages are skipped, the actual total number of pages to print will not be known until the printing process is complete. This may impact print process tracking if the initial expected number of pages is greater than the number actually printed.

Examples

Shows how to filtering pages using a page number list.

public void PageIndexFilter()
{
    Document doc = new Document(MyDir + "Rendering.docx");

    // Configure printer settings and create print document.
    PrinterSettings printerSettings = new PrinterSettings();
    AsposeWordsPrintDocument printDoc = new AsposeWordsPrintDocument(doc);
    printDoc.PrinterSettings = printerSettings;

    // Set the target printer.
    printerSettings.PrinterName = "Microsoft Print to PDF";

    // Set page range to print all pages.
    printerSettings.FromPage = 1;
    printerSettings.ToPage = doc.PageCount;

    // The test document has 5 pages. To skip pages 2, 4, and 5,
    // specify the zero-based indices of pages to exclude.
    HashSet<int> pagesToSkip = new HashSet<int>() { 1, 3, 4 };

    // Apply the page filter to skip specified pages.
    printDoc.PageIndexFilter = new PrintPagesFilter(pagesToSkip);

    // Initialize custom printing tracker.
    PrintTracker printTracker = new PrintTracker(printDoc);

    // Print the document (only pages 1 and 3 will be printed).
    printDoc.Print();
}

/// <summary>
/// Filter for skipping specified pages during printing.
/// </summary>
internal sealed class PrintPagesFilter : IIndexFilter
{
    private readonly HashSet<int> _pagesToSkip;

    /// <summary>
    /// Initializes a new instance of the <see cref="PrintPagesFilter"/> class.
    /// </summary>
    /// <param name="pagesToSkip">The collection of page indices to skip.</param>
    /// <exception cref="ArgumentNullException">Thrown when <paramref name="pagesToSkip"/> is null.</exception>
    public PrintPagesFilter(HashSet<int> pagesToSkip)
    {
        if (pagesToSkip == null)
            throw new ArgumentNullException(nameof(pagesToSkip));

        _pagesToSkip = pagesToSkip;
    }

    public bool ShouldSkipIndex(int index)
    {
        if (index < 0)
            throw new ArgumentOutOfRangeException(nameof(index), "Index cannot be negative.");

        return _pagesToSkip.Contains(index);
    }
}

Shows how to filtering pages base on page color.

public void ColorMode()
{
    // Load the document with 3 color pages and 2 black and white pages.
    Document doc = new Document(MyDir + "Colored pages.docx");

    // Print color pages to 'color' printer.
    int colorPagesPrinted = PrintPages(doc, "Microsoft Print to PDF", true);

    // Print black-and-white pages to 'black-and-white' printer.
    int nonColorPagesPrinted = PrintPages(doc, "Microsoft XPS Document Writer", false);

    // Verify that correct number of pages were printed in each case.
    Assert.That(colorPagesPrinted, Is.EqualTo(3));
    Assert.That(nonColorPagesPrinted, Is.EqualTo(3));
}

/// <summary>
/// Prints document pages filtered by color requirements.
/// </summary>
/// <param name="doc">The document to print.</param>
/// <param name="printerName">The name of the target printer.</param>
/// <param name="colored">
/// <c>true</c> to print only color pages; 
/// <c>false</c> to print only black and white pages.
/// </param>
/// <returns>The number of pages actually printed.</returns>
private int PrintPages(Document doc, string printerName, bool colored)
{
    // Configure printer settings.
    PrinterSettings printerSettings = new PrinterSettings();
    printerSettings.PrinterName = printerName;
    printerSettings.FromPage = 1;
    printerSettings.ToPage = doc.PageCount;

    // Create print document with color mode set to Normal.
    AsposeWordsPrintDocument printDoc = new AsposeWordsPrintDocument(doc);
    printDoc.PrinterSettings = printerSettings;
    printDoc.ColorMode = ColorPrintMode.Normal;

    // Filter pages: skip color pages when printing black and white, and vice versa.
    printDoc.PageIndexFilter = new ColorPagesFilter(doc, !colored);

    printDoc.Print();

    return printDoc.TotalPagesPrinted;
}

/// <summary>
/// A filter that selectively skips color or black-and-white pages during printing
/// based on the document's page information and specified filtering mode.
/// </summary>
/// <remarks>
/// This filter implements the IIndexFilter interface to provide custom page selection
/// logic for printing operations. It can be configured to either skip color pages
/// (when printing only black-and-white content) or skip black-and-white pages
/// (when printing only color content).
/// </remarks>
internal class ColorPagesFilter : IIndexFilter
{
    private readonly Document _doc;
    private readonly bool _skipColorPages;

    /// <summary>
    /// Initializes a new instance of the ColorPagesFilter class.
    /// </summary>
    /// <param name="doc">The document containing page information.</param>
    /// <param name="skipColorPages">
    /// If true, the filter will skip color pages (print only black-and-white pages).
    /// If false, the filter will skip black-and-white pages (print only color pages).
    /// </param>
    public ColorPagesFilter(Document doc, bool skipColorPages)
    {
        _doc = doc;
        _skipColorPages = skipColorPages;
    }

    /// <summary>
    /// Determines whether the page at the specified index should be skipped during printing.
    /// </summary>
    /// <param name="index">The zero-based page index to check.</param>
    /// <returns>
    /// true if the page should be skipped; otherwise, false.
    /// The decision is based on the page's color information and the filter configuration:
    /// - Returns true when the page's color status matches the skip condition.
    /// - Returns false when the page should be printed.
    /// </returns>
    public bool ShouldSkipIndex(int index)
    {
        return _skipColorPages == _doc.GetPageInfo(index).Colored;
    }
}

See Also

AsposeWordsPrintDocument.ColorPagesPrinted AsposeWordsPrintDocument.PagesRemaining