Search and Replace Text in PowerPoint Presentations in .NET

What this page is about

Search, highlight, and replace text in PowerPoint presentations while collecting every match with Aspose.Slides for .NET.

Overview

Aspose.Slides for .NET can search, highlight, and replace text in an individual text frame or across an entire presentation. Each operation can also notify an application about every match through a result callback. This makes it possible to update a presentation and simultaneously build an audit trail containing the matched text, its context, position, text frame, and slide number.

These capabilities are useful for review, redaction, terminology checks, template cleanup, and automated reporting workflows.

In the first examples below, we use a file named “sample.pptx”, which contains a single text box on the first slide with the following text:

Choose the Search Scope

Use methods on ITextFrame to limit an operation to one text frame. Use methods on Presentation to process all applicable text in the presentation.

Operation	One text frame	Entire presentation
Highlight literal text	ITextFrame.HighlightText	Presentation.HighlightText
Highlight regular-expression matches	ITextFrame.HighlightRegex	Presentation.HighlightRegex
Replace literal text	ITextFrame.ReplaceText	Presentation.ReplaceText
Replace regular-expression matches	ITextFrame.ReplaceRegex	Presentation.ReplaceRegex

Configure Text Matching

For literal-text operations, use TextSearchOptions to control matching:

• TextSearchOptions.WholeWordsOnly limits matches to complete words.
• TextSearchOptions.CaseSensitive controls whether character case must match.
• TextSearchOptions.IncludeNotes includes slide notes in presentation-level search, replacement, and highlighting operations.

Regular-expression operations use a .NET Regex, so matching rules such as case sensitivity and word boundaries are defined by the expression and its options.

Collect Match Information with a Callback

Implement IFindResultCallback to receive a notification for every match. Its IFindResultCallback.FoundResult method provides the related text frame, the source text, the matched text, and the match position.

The callback does not receive a slide number directly. The implementation below derives it from the parent slide and also handles text found in slide notes. A nullable slide number allows the same result model to represent text associated with other slide types.

using System.Collections.Generic;
using Aspose.Slides;

public sealed class TextMatch
{
    public TextMatch(ITextFrame textFrame, string sourceText, string foundText, int textPosition, int? slideNumber)
    {
        TextFrame = textFrame;
        SourceText = sourceText;
        FoundText = foundText;
        TextPosition = textPosition;
        SlideNumber = slideNumber;
    }

    public ITextFrame TextFrame { get; }
    public string SourceText { get; }
    public string FoundText { get; }
    public int TextPosition { get; }
    public int? SlideNumber { get; }
}

public sealed class TextSearchCallback : IFindResultCallback
{
    public List<TextMatch> Results { get; } = new();

    public void FoundResult(ITextFrame textFrame, string sourceText, string foundText, int textPosition)
    {
        var slideNumber = GetSlideNumber(textFrame);
        var result = new TextMatch(textFrame, sourceText, foundText, textPosition, slideNumber);

        Results.Add(result);
    }

    private static int? GetSlideNumber(ITextFrame textFrame)
    {
        if (textFrame is not TextFrame concreteTextFrame)
        {
            return null;
        }

        var parentSlide = concreteTextFrame.Slide;

        if (parentSlide is ISlide slide)
        {
            return slide.SlideNumber;
        }

        if (parentSlide is INotesSlide notesSlide)
        {
            return notesSlide.ParentSlide.SlideNumber;
        }

        return null;
    }
}

For replacement operations, FoundText contains the original matched text, so the callback can record exactly which terms were replaced.

Highlight Text

Use the ITextFrame.HighlightText method to highlight literal-text matches in a text frame. Pass TextSearchOptions to control the search and a callback to collect match details.

The code example below highlights all occurrences of the characters “try” and then highlights only the complete word “to”. Both searches report their matches to the same callback.

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

using var presentation = new Presentation("sample.pptx");

// Get the first shape from the first slide.
var shape = (IAutoShape)presentation.Slides[0].Shapes[0];
var callback = new TextSearchCallback();

var substringSearchOptions = new TextSearchOptions
{
    CaseSensitive = false
};

// Highlight every occurrence of "try" in the text frame.
shape.TextFrame.HighlightText("try", Color.LightBlue, substringSearchOptions, callback);

var wholeWordSearchOptions = new TextSearchOptions
{
    WholeWordsOnly = true,
    CaseSensitive = false
};

// Highlight only the complete word "to".
shape.TextFrame.HighlightText("to", Color.Violet, wholeWordSearchOptions, callback);

foreach (var result in callback.Results)
{
    Console.WriteLine($"Found '{result.FoundText}' at position {result.TextPosition} on slide {result.SlideNumber}.");
}

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

The result:

Highlight Text Using Regular Expressions

The ITextFrame.HighlightRegex method highlights text matches found by a regular expression in a text frame.

The following code highlights all words containing seven or more characters and collects each match:

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

using var presentation = new Presentation("sample.pptx");

var shape = (IAutoShape)presentation.Slides[0].Shapes[0];
var callback = new TextSearchCallback();
var regex = new Regex(@"\b[^\s]{7,}\b");

shape.TextFrame.HighlightRegex(regex, Color.Yellow, callback);

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

The result:

Highlight Text Across a Presentation

Use Presentation.HighlightText and Presentation.HighlightRegex to search all applicable text frames in a presentation. The following example highlights a literal term and all email addresses while keeping separate result collections for the two searches.

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

using var presentation = new Presentation("presentation.pptx");

var termCallback = new TextSearchCallback();
var searchOptions = new TextSearchOptions
{
    WholeWordsOnly = true,
    CaseSensitive = false
};

presentation.HighlightText("confidential", Color.Orange, searchOptions, termCallback);

var emailCallback = new TextSearchCallback();
var emailRegex = new Regex(@"\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}\b", RegexOptions.IgnoreCase);

presentation.HighlightRegex(emailRegex, Color.Yellow, emailCallback);

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

Replace Text in a Text Frame

Use ITextFrame.ReplaceText for literal text and ITextFrame.ReplaceRegex for pattern-based replacement. These methods update matched text within the existing text frame, which retains the surrounding portion formatting instead of rebuilding the text frame from a plain string.

The following example standardizes a spelling variant and then replaces version labels. The same callback records the original terms matched by both operations.

using System.Text.RegularExpressions;
using Aspose.Slides;
using Aspose.Slides.Export;

using var presentation = new Presentation("presentation.pptx");

var shape = (IAutoShape)presentation.Slides[0].Shapes[0];
var callback = new TextSearchCallback();
var searchOptions = new TextSearchOptions
{
    WholeWordsOnly = true,
    CaseSensitive = false
};

shape.TextFrame.ReplaceText("colour", "color", searchOptions, callback);

var versionRegex = new Regex(@"\bv\d+(?:\.\d+)*\b", RegexOptions.IgnoreCase);
shape.TextFrame.ReplaceRegex(versionRegex, "current version", callback);

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

If one match spans portions with different formatting, review the output to confirm which formatting should apply to the replacement text.

Replace Text Across a Presentation

Use Presentation.ReplaceText and Presentation.ReplaceRegex to apply the same operations across the presentation. This is useful for template cleanup, terminology updates, and redaction.

using System.Text.RegularExpressions;
using Aspose.Slides;
using Aspose.Slides.Export;

using var presentation = new Presentation("presentation.pptx");

var callback = new TextSearchCallback();
var searchOptions = new TextSearchOptions
{
    WholeWordsOnly = true,
    CaseSensitive = true
};

presentation.ReplaceText("Contoso", "Example Corp", searchOptions, callback);

var accountNumberRegex = new Regex(@"\bACCT-\d{6}\b");
presentation.ReplaceRegex(accountNumberRegex, "ACCT-REDACTED", callback);

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

Group Matches for Reporting

Because every result stores its slide number and text frame, applications can group matches for audit, reporting, or review workflows. The following example groups the collected results first by slide and then by text frame:

using System;
using System.Linq;

var matchesBySlide = callback.Results.GroupBy(result => result.SlideNumber);

foreach (var slideGroup in matchesBySlide)
{
    var slideLabel = slideGroup.Key.HasValue ? slideGroup.Key.Value.ToString() : "Other";
    Console.WriteLine($"Slide: {slideLabel}");

    var matchesByTextFrame = slideGroup.GroupBy(result => result.TextFrame);
    foreach (var textFrameGroup in matchesByTextFrame)
    {
        Console.WriteLine($"  Text frame: {textFrameGroup.Key.Text}");

        foreach (var result in textFrameGroup)
        {
            Console.WriteLine($"    '{result.FoundText}' at position {result.TextPosition}; context: '{result.SourceText}'");
        }
    }
}

FAQ

How can I search only one text box instead of the entire presentation?

Get the shape’s text frame and call ITextFrame.HighlightText, ITextFrame.HighlightRegex, ITextFrame.ReplaceText, or ITextFrame.ReplaceRegex on that text frame. Presentation-level methods process all applicable text frames instead.

How can I match complete words with the correct capitalization?

Set TextSearchOptions.WholeWordsOnly and TextSearchOptions.CaseSensitive to true, and pass the options to a literal-text highlighting or replacement method. For regular expressions, define word boundaries and case sensitivity in the .NET Regex itself.

Can search and replacement include text in slide notes?

Yes. Set TextSearchOptions.IncludeNotes to true when using a presentation-level literal-text operation. The callback implementation shown above maps a match in a notes slide back to its parent slide number.

How can I create a report without scanning the presentation a second time?

Pass an IFindResultCallback implementation to the highlighting or replacement operation. The callback receives every match while the operation runs, so the application can store the source text, matched text, position, text frame, and derived slide number for later grouping or export.

Does replacing text preserve its formatting?

ITextFrame.ReplaceText and ITextFrame.ReplaceRegex modify matched text within the existing text frame and retain the surrounding portion formatting. If a match spans portions with different formatting, inspect the result to ensure the replacement uses the desired style.