Get all the text in all slides in a presentation
This topic shows how to use the classes in the Open XML SDK to get all of the text in all of the slides in a presentation programmatically.
Getting a PresentationDocument object
In the Open XML SDK, the PresentationDocument class represents a presentation document package. To work with a presentation document, first create an instance of the PresentationDocument class, and then work with that instance. To create the class instance from the document call the PresentationDocument.Open(String, Boolean) method that uses a file path, and a Boolean value as the second parameter to specify whether a document is editable. To open a document for read/write access, assign the value true to this parameter; for read-only access assign it the value false as shown in the following using statement. In this code, the presentationFile parameter is a string that represents the path for the file from which you want to open the document.
// Open the presentation as read-only.
using (PresentationDocument presentationDocument = PresentationDocument.Open(presentationFile, false))
{
// Insert other code here.
}
The using statement provides a recommended alternative to the typical .Open, .Save, .Close sequence. It ensures that the Dispose method (internal method used by the Open XML SDK to clean up resources) is automatically called when the closing brace is reached. The block that follows the using statement establishes a scope for the object that is created or named in the using statement, in this case presentationDocument.
Basic Presentation Document Structure
The basic document structure of a PresentationML document consists of a number of parts, among which is the main part that contains the presentation definition. The following text from the ISO/IEC 29500 specification introduces the overall form of a PresentationML package.
The main part of a PresentationML package starts with a presentation root element. That element contains a presentation, which, in turn, refers to a slide list, a slide master list, a notes master list, and a handout master list. The slide list refers to all of the slides in the presentation; the slide master list refers to the entire slide masters used in the presentation; the notes master contains information about the formatting of notes pages; and the handout master describes how a handout looks.
A handout is a printed set of slides that can be provided to an audience.
As well as text and graphics, each slide can contain comments and notes, can have a layout, and can be part of one or more custom presentations. A comment is an annotation intended for the person maintaining the presentation slide deck. A note is a reminder or piece of text intended for the presenter or the audience.
Other features that a PresentationML document can include the following: animation, audio, video, and transitions between slides.
A PresentationML document is not stored as one large body in a single part. Instead, the elements that implement certain groupings of functionality are stored in separate parts. For example, all comments in a document are stored in one comment part while each slide has its own part.
© ISO/IEC29500: 2008.
The following XML code example represents a presentation that contains two slides denoted by the IDs 267 and 256.
<p:presentation xmlns:p="…" … >
<p:sldMasterIdLst>
<p:sldMasterId
xmlns:rel="https://…/relationships" rel:id="rId1"/>
</p:sldMasterIdLst>
<p:notesMasterIdLst>
<p:notesMasterId
xmlns:rel="https://…/relationships" rel:id="rId4"/>
</p:notesMasterIdLst>
<p:handoutMasterIdLst>
<p:handoutMasterId
xmlns:rel="https://…/relationships" rel:id="rId5"/>
</p:handoutMasterIdLst>
<p:sldIdLst>
<p:sldId id="267"
xmlns:rel="https://…/relationships" rel:id="rId2"/>
<p:sldId id="256"
xmlns:rel="https://…/relationships" rel:id="rId3"/>
</p:sldIdLst>
<p:sldSz cx="9144000" cy="6858000"/>
<p:notesSz cx="6858000" cy="9144000"/>
</p:presentation>
Using the Open XML SDK, you can create document structure and content using strongly-typed classes that correspond to PresentationML elements. You can find these classes in the DocumentFormat.OpenXml.Presentation namespace. The following table lists the class names of the classes that correspond to the sld, sldLayout, sldMaster, and notesMaster elements.
| PresentationML Element | Open XML SDK Class | Description |
|---|---|---|
| sld | Slide | Presentation Slide. It is the root element of SlidePart. |
| sldLayout | SlideLayout | Slide Layout. It is the root element of SlideLayoutPart. |
| sldMaster | SlideMaster | Slide Master. It is the root element of SlideMasterPart. |
| notesMaster | NotesMaster | Notes Master (or handoutMaster). It is the root element of NotesMasterPart. |
Sample Code
The following code gets all the text in all the slides in a specific presentation file. For example, you can enter the name of the presentation file from the keyboard, and then use a foreach loop in your program to get the array of strings returned by the method GetSlideIdAndText as shown in the following example.
Console.Write("Please enter a presentation file name without extension: ");
string fileName = Console.ReadLine();
string file = @"C:\Users\Public\Documents\" + fileName + ".pptx";
int numberOfSlides = CountSlides(file);
System.Console.WriteLine("Number of slides = {0}", numberOfSlides);
string slideText;
for (int i = 0; i < numberOfSlides; i++)
{
GetSlideIdAndText(out slideText, file, i);
System.Console.WriteLine("Slide #{0} contains: {1}", i + 1, slideText);
}
System.Console.ReadKey();
The following is the complete sample code in both C# and Visual Basic.
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Presentation;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using A = DocumentFormat.OpenXml.Drawing;
if (args is [{ } sldText, { } slideIndex])
{
GetSlideIdAndText(out string text, sldText, int.Parse(slideIndex));
}
if (args is [{ } presentationFile])
{
CountSlides(presentationFile);
}
static int CountSlides(string presentationFile)
{
// Open the presentation as read-only.
using (PresentationDocument presentationDocument = PresentationDocument.Open(presentationFile, false))
{
// Pass the presentation to the next CountSlides method
// and return the slide count.
return CountSlidesFromPresentation(presentationDocument);
}
}
// Count the slides in the presentation.
static int CountSlidesFromPresentation(PresentationDocument presentationDocument)
{
// Check for a null document object.
if (presentationDocument is null)
{
throw new ArgumentNullException("presentationDocument");
}
int slidesCount = 0;
// Get the presentation part of document.
PresentationPart? presentationPart = presentationDocument.PresentationPart;
// Get the slide count from the SlideParts.
if (presentationPart is not null)
{
slidesCount = presentationPart.SlideParts.Count();
}
// Return the slide count to the previous method.
return slidesCount;
}
static void GetSlideIdAndText(out string sldText, string docName, int index)
{
using (PresentationDocument ppt = PresentationDocument.Open(docName, false))
{
// Get the relationship ID of the first slide.
PresentationPart? part = ppt.PresentationPart;
OpenXmlElementList slideIds = part?.Presentation?.SlideIdList?.ChildElements ?? default;
if (part is null || slideIds.Count == 0)
{
sldText = "";
return;
}
string? relId = ((SlideId)slideIds[index]).RelationshipId;
if (relId is null)
{
sldText = "";
return;
}
// Get the slide part from the relationship ID.
SlidePart slide = (SlidePart)part.GetPartById(relId);
// Build a StringBuilder object.
StringBuilder paragraphText = new StringBuilder();
// Get the inner text of the slide:
IEnumerable<A.Text> texts = slide.Slide.Descendants<A.Text>();
foreach (A.Text text in texts)
{
paragraphText.Append(text.Text);
}
sldText = paragraphText.ToString();
}
}