Manage Bulleted and Numbered Lists in Presentations in .NET

What this page is about

Learn how to create and format bulleted, picture, multilevel, and numbered lists in PowerPoint and OpenDocument presentations using Aspose.Slides for .NET.

Overview

Aspose.Slides for .NET lets you create and format bulleted and numbered lists in PowerPoint and OpenDocument presentations. A list item is a paragraph whose bullet settings are controlled through its paragraph format.

Use the IParagraph.ParagraphFormat property to access paragraph-level list settings. The main entry point is IParagraphFormat.Bullet, which returns an IBulletFormat object. With this object, you can set the bullet type, symbol, picture, color, size, numbering style, and starting number.

This article shows how to:

create a bulleted list with a custom symbol
create a picture bullet
create a multilevel list by setting paragraph depth
create a numbered list
inspect and change list formatting in an existing presentation
read actual list markers and numbers alongside paragraph text

Create a Bulleted List

To create a bulleted list, add IParagraph objects to an ITextFrame and set IBulletFormat.Type to BulletType.Symbol. You can then set IBulletFormat.Char, IBulletFormat.Color, and IBulletFormat.Height to control the bullet appearance.

The following C# code demonstrates how to create a bulleted list in a slide:

using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

static Paragraph CreateParagraph(string text)
{
    var paragraph = new Paragraph();
    paragraph.ParagraphFormat.Bullet.Type = BulletType.Symbol;
    paragraph.ParagraphFormat.Bullet.Char = '*';
    paragraph.ParagraphFormat.Indent = 15;
    paragraph.ParagraphFormat.Bullet.IsBulletHardColor = NullableBool.True;
    paragraph.ParagraphFormat.Bullet.Color.Color = Color.IndianRed;
    paragraph.ParagraphFormat.Bullet.Height = 100;
    paragraph.Text = text;
    return paragraph;
}

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 20, 20, 200, 50);

var textFrame = autoShape.TextFrame;
textFrame.Paragraphs.Clear();

var paragraph1 = CreateParagraph("The first paragraph");
textFrame.Paragraphs.Add(paragraph1);

var paragraph2 = CreateParagraph("The second paragraph");
textFrame.Paragraphs.Add(paragraph2);

presentation.Save("symbol_bullets.pptx", SaveFormat.Pptx);

The result:

The symbol bullets

Create a Numbered List

Use numbered lists when the order of items matters. Set IBulletFormat.Type to BulletType.Numbered. You can also choose a numbering format with IBulletFormat.NumberedBulletStyle or set IBulletFormat.NumberedBulletStartWith when the list should start from a value other than 1.

The following C# code shows how to create a numbered list in a slide:

using Aspose.Slides;
using Aspose.Slides.Export;

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 20, 20, 90, 80);

var textFrame = autoShape.TextFrame;
textFrame.Paragraphs.Clear();

var paragraph1 = new Paragraph();
paragraph1.ParagraphFormat.Bullet.Type = BulletType.Numbered;
paragraph1.Text = "Apple";
textFrame.Paragraphs.Add(paragraph1);

var paragraph2 = new Paragraph();
paragraph2.ParagraphFormat.Bullet.Type = BulletType.Numbered;
paragraph2.Text = "Orange";
textFrame.Paragraphs.Add(paragraph2);

var paragraph3 = new Paragraph();
paragraph3.ParagraphFormat.Bullet.Type = BulletType.Numbered;
paragraph3.Text = "Banana";
textFrame.Paragraphs.Add(paragraph3);

presentation.Save("numbered_bullets.pptx", SaveFormat.Pptx);

The result:

The numbered bullets

Create a Picture Bullet

Aspose.Slides allows you to replace a regular bullet symbol with an image. Picture bullets work best with simple images that remain readable at a small size, such as icons or small transparent PNG files.

Note

Ideally, if you plan to replace the regular bullet symbol with an image, it’s best to choose a simple graphic with a transparent background. Such images work well as custom bullet symbols.

Keep in mind that the image will be scaled down to a very small size. For that reason, we strongly recommend selecting an image that remains clear and visually effective when used as a bullet in a list.

To create a picture bullet, add an image to Presentation.Images and assign the returned image object to IBulletFormat.Picture. Set IBulletFormat.Type to BulletType.Picture before assigning the image.

Let’s say we have an “image.png”:

A picture for the bullets

The following C# code shows how to create picture bullets in a slide:

using Aspose.Slides;
using Aspose.Slides.Export;

static Paragraph CreateParagraph(string text, IPPImage image)
{
    var paragraph = new Paragraph();
    paragraph.ParagraphFormat.Bullet.Type = BulletType.Picture;
    paragraph.ParagraphFormat.Bullet.Picture.Image = image;
    paragraph.ParagraphFormat.Indent = 15;
    paragraph.ParagraphFormat.Bullet.Height = 100;
    paragraph.Text = text;
    return paragraph;
}

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 20, 20, 200, 50);

var textFrame = autoShape.TextFrame;
textFrame.Paragraphs.Clear();

var imageBytes = File.ReadAllBytes("image.png");
var bulletImage = presentation.Images.AddImage(imageBytes);

var paragraph1 = CreateParagraph("The first paragraph", bulletImage);
textFrame.Paragraphs.Add(paragraph1);

var paragraph2 = CreateParagraph("The second paragraph", bulletImage);
textFrame.Paragraphs.Add(paragraph2);

presentation.Save("picture_bullets.pptx", SaveFormat.Pptx);

The result:

The picture bullets

Create a Multilevel List

Use IParagraphFormat.Depth to place list items on different levels. Level 0 is the top level, level 1 is nested below it, and so on.

The following C# code shows how to create a multilevel bulleted list:

using Aspose.Slides;
using Aspose.Slides.Export;

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var autoShape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 20, 20, 260, 110);

var textFrame = autoShape.TextFrame;
textFrame.Paragraphs.Clear();

var paragraph1 = new Paragraph();
paragraph1.ParagraphFormat.Depth = 0;
paragraph1.Text = "My text - Depth 0";
textFrame.Paragraphs.Add(paragraph1);

var paragraph2 = new Paragraph();
paragraph2.ParagraphFormat.Depth = 1;
paragraph2.Text = "My text - Depth 1";
textFrame.Paragraphs.Add(paragraph2);

var paragraph3 = new Paragraph();
paragraph3.ParagraphFormat.Depth = 2;
paragraph3.Text = "My text - Depth 2";
textFrame.Paragraphs.Add(paragraph3);

var paragraph4 = new Paragraph();
paragraph4.ParagraphFormat.Depth = 3;
paragraph4.Text = "My text - Depth 3";
textFrame.Paragraphs.Add(paragraph4);

presentation.Save("multilevel_bullets.pptx", SaveFormat.Pptx);

The result:

The multilevel list

Change an Existing List

To change list formatting in an existing presentation, access the target paragraph and update its IParagraphFormat.Bullet settings. The same properties used to create lists can be used to inspect or modify lists loaded from a PPT, PPTX, or ODP file.

The following C# code changes the first paragraph in a text frame to use a numbered list style:

using Aspose.Slides;
using Aspose.Slides.Export;

using var presentation = new Presentation("input.pptx");
var slide = presentation.Slides[0];
var autoShape = (IAutoShape)slide.Shapes[0];

var paragraph = autoShape.TextFrame.Paragraphs[0];
paragraph.ParagraphFormat.Bullet.Type = BulletType.Numbered;
paragraph.ParagraphFormat.Bullet.NumberedBulletStyle = NumberedBulletStyle.BulletRomanUCPeriod;
paragraph.ParagraphFormat.Bullet.NumberedBulletStartWith = 1;
paragraph.ParagraphFormat.MarginLeft = 30;
paragraph.ParagraphFormat.Indent = -20;

presentation.Save("updated_list.pptx", SaveFormat.Pptx);

Read Actual Bullet Values

When extracting presentation content, keep list markers alongside paragraph text. Call IParagraphFormat.GetEffective and access IParagraphFormatEffectiveData.Bullet to obtain the effective bullet format. Check its Type before reading ActualBulletValue.

For numbered lists, distinguish these three values:

NumberedBulletStyle determines the format, such as Arabic numbers followed by a period or lowercase letters followed by a period.
NumberedBulletStartWith specifies the starting number for a group of numbered paragraphs.
ActualBulletValue returns the formatted marker for a particular paragraph. For example, the second item in a list starting at 5 returns 6..

Preserve Depth with each paragraph to retain its nesting level. The actual marker does not encode the full hierarchy: a nested item can return c. rather than a combined label such as 6.c..

The following self-contained example creates lists, saves them to a presentation, and reloads the presentation to report each paragraph’s text, depth, bullet type, and actual value. The small blue picture marker is created from inline SVG.

using System;
using System.Drawing;
using Aspose.Slides;
using Aspose.Slides.Export;

using (var presentation = new Presentation())
{
    presentation.SlideSize.SetSize(720, 440, SlideSizeScaleType.DoNotScale);
    var slide = presentation.Slides[0];

    var shape = slide.Shapes.AddAutoShape(ShapeType.Rectangle, 30, 20, 660, 400);
    shape.FillFormat.FillType = FillType.NoFill;
    shape.LineFormat.FillFormat.FillType = FillType.NoFill;

    var textFrame = shape.TextFrame;
    textFrame.Paragraphs.Clear();

    // Create a picture marker without an external image file.
    var svg = new SvgImage("<svg xmlns='http://www.w3.org/2000/svg' width='16' height='16'><rect width='16' height='16' rx='4' fill='#0078D4'/></svg>");
    var bulletImage = presentation.Images.AddImage(svg);

    void AddParagraph(string text, short depth, BulletType type, short start = 1, NumberedBulletStyle style = NumberedBulletStyle.BulletArabicPeriod)
    {
        var paragraph = new Paragraph { Text = text };

        var format = paragraph.ParagraphFormat;
        format.Depth = depth;
        format.MarginLeft = 30 + depth * 40;
        format.Indent = -28;
        format.SpaceAfter = 8;
        format.DefaultPortionFormat.FontHeight = 22;
        format.DefaultPortionFormat.FillFormat.FillType = FillType.Solid;
        format.DefaultPortionFormat.FillFormat.SolidFillColor.Color = Color.Black;
        format.Bullet.Type = type;
        format.Bullet.IsBulletHardColor = NullableBool.True;
        format.Bullet.Color.Color = Color.Black;
        if (type == BulletType.Numbered)
        {
            format.Bullet.NumberedBulletStyle = style;
            format.Bullet.NumberedBulletStartWith = start;
        }
        else if (type == BulletType.Symbol)
        {
            format.Bullet.Char = '\u2022';
        }
        else if (type == BulletType.Picture)
        {
            format.Bullet.Picture.Image = bulletImage;
        }

        textFrame.Paragraphs.Add(paragraph);
    }

    AddParagraph("First item", 0, BulletType.Numbered, 5);
    AddParagraph("Second item", 0, BulletType.Numbered, 5);
    AddParagraph("Nested item", 1, BulletType.Numbered, 3, NumberedBulletStyle.BulletAlphaLCPeriod);
    AddParagraph("Next nested item", 1, BulletType.Numbered, 3, NumberedBulletStyle.BulletAlphaLCPeriod);
    AddParagraph("Deep item", 2, BulletType.Numbered, 4, NumberedBulletStyle.BulletRomanLCPeriod);
    AddParagraph("Back to top level", 0, BulletType.Numbered, 5);
    AddParagraph("Symbol marker", 0, BulletType.Symbol);
    AddParagraph("No bullet", 0, BulletType.None);
    AddParagraph("Picture marker", 0, BulletType.Picture);
    presentation.Save("actual_bullet_values.pptx", SaveFormat.Pptx);
}

using var loadedPresentation = new Presentation("actual_bullet_values.pptx");
var loadedShape = (IAutoShape)loadedPresentation.Slides[0].Shapes[0];
Console.WriteLine("Text | Depth | Type | Actual value");
foreach (var paragraph in loadedShape.TextFrame.Paragraphs)
{
    var bullet = paragraph.ParagraphFormat.GetEffective().Bullet;
    string marker;
    switch (bullet.Type)
    {
        case BulletType.Numbered:
        case BulletType.Symbol:
            marker = bullet.ActualBulletValue;
            break;
        case BulletType.None:
            marker = $"{bullet.ActualBulletValue ?? "null"} (no bullet)";
            break;
        case BulletType.Picture:
            marker = $"{bullet.ActualBulletValue ?? "null"} (image required)";
            break;
        default:
            marker = "unsupported bullet type";
            break;
    }
    Console.WriteLine($"{paragraph.Text} | {paragraph.ParagraphFormat.Depth} | {bullet.Type} | {marker}");
}

The source lists are shown below.

Lists starting at 5, nested letter and Roman-number items, a symbol marker, a paragraph without a bullet, and a blue picture marker

The report matches the markers displayed in PowerPoint:

Text | Depth | Type | Actual value
First item | 0 | Numbered | 5.
Second item | 0 | Numbered | 6.
Nested item | 1 | Numbered | c.
Next nested item | 1 | Numbered | d.
Deep item | 2 | Numbered | iv.
Back to top level | 0 | Numbered | 7.
Symbol marker | 0 | Symbol | •
No bullet | 0 | None | null (no bullet)
Picture marker | 0 | Picture | null (image required)

For BulletType.None and BulletType.Picture, ActualBulletValue returns null, not an empty string. Handle these types separately: the former has no marker, while the latter requires extracting the bullet image separately. A picture bullet cannot be reproduced solely by extracting a text marker.

FAQ

Can bulleted and numbered lists be exported to PDF or images?

Yes. Aspose.Slides preserves list formatting when the target format supports the corresponding text layout and bullet features.

Can I edit lists in existing presentations?

Yes. Load the presentation, access the target paragraph, inspect or update its IParagraphFormat.Bullet settings, and save the presentation.

Can lists contain non-Latin text?

Yes. List item text can contain Unicode characters, so you can create lists in multilingual presentations. Make sure the fonts used in the presentation support the characters you need.

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Manage Bulleted and Numbered Lists in Presentations in .NET

What this page is about

Overview

Create a Bulleted List

Create a Numbered List

Create a Picture Bullet

Note

Create a Multilevel List

Change an Existing List

Read Actual Bullet Values

FAQ

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