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How to: Get All the Text in All Slides in a Presentation

  • Artigo

Applies to: Excel 2010 | Office 2010 | PowerPoint 2010 | Word 2010

In this article
Getting a PresentationDocument object
Basic Presentation Document Structure
How the Sample Code Works
Sample Code

This topic shows how to use the classes in the Open XML SDK 2.0 for Microsoft Office to get all of the text in all of the slides in a presentation programmatically.

The following assembly directives are required to compile the code in this topic.

using System;
using System.Linq;
using System.Collections.Generic;
using DocumentFormat.OpenXml.Presentation;
using A = DocumentFormat.OpenXml.Drawing;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml;
using System.Text;

Imports System
Imports System.Linq
Imports System.Collections.Generic
Imports A = DocumentFormat.OpenXml.Drawing
Imports DocumentFormat.OpenXml.Presentation
Imports DocumentFormat.OpenXml.Packaging
Imports DocumentFormat.OpenXml
Imports System.Text

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.
}

Using presentationDocument As PresentationDocument = PresentationDocument.Open(presentationFile, False)
    ' Insert other code here.
End Using

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.

A PresentationML package’s main part 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 for future reference.

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 contain 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 segment represents a presentation that contains two slides denoted by the ID 267 and 256.

<p:presentation xmlns:p="…" … > 
   <p:sldMasterIdLst>
      <p:sldMasterId
         xmlns:rel="http://…/relationships" rel:id="rId1"/>
   </p:sldMasterIdLst>
   <p:notesMasterIdLst>
      <p:notesMasterId
         xmlns:rel="http://…/relationships" rel:id="rId4"/>
   </p:notesMasterIdLst>
   <p:handoutMasterIdLst>
      <p:handoutMasterId
         xmlns:rel="http://…/relationships" rel:id="rId5"/>
   </p:handoutMasterIdLst>
   <p:sldIdLst>
      <p:sldId id="267"
         xmlns:rel="http://…/relationships" rel:id="rId2"/>
      <p:sldId id="256"
         xmlns:rel="http://…/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 2.0, 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 2.0 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.

How the Sample Code Works

The sample code starts by counting the number of slides in the presentation. It does that by using two overloads of the method CountSlides. The first overload uses a string parameter and the second overload uses a PresentationDocument parameter. In the first CountSlides method, the sample code opens the presentation document in the using statement. Then it passes the PresentationDocument object to the second CountSlides method, which returns an integer number that represents the number of slides in the presentation.

// Pass the presentation to the next CountSlides method
// and return the slide count.
return CountSlides(presentationDocument);

' Pass the presentation to the next CountSlides method
' and return the slide count.
Return CountSlides(presentationDocument)

In the second CountSlides method, the code verifies that the PresentationDocument object passed in is not null, and if it is not, it gets a PresentationPart object from the PresentationDocument object. By using the Count method, which belongs to SlideParts, the code gets the slidesCount and returns it.

// Check for a null document object.
if (presentationDocument == 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 != null)
{
    slidesCount = presentationPart.SlideParts.Count();
}
// Return the slide count to the previous method.
return slidesCount;

' Check for a null document object.
If presentationDocument Is Nothing Then
    Throw New ArgumentNullException("presentationDocument")
End If

Dim slidesCount As Integer = 0

' Get the presentation part of document.
Dim presentationPart As PresentationPart = presentationDocument.PresentationPart

' Get the slide count from the SlideParts.
If presentationPart IsNot Nothing Then
    slidesCount = presentationPart.SlideParts.Count()
End If
' Return the slide count to the previous method.
Return slidesCount

After counting the number of slides, the code uses the method GetSlideIdAndTextto get the content of all the slides. It starts with getting the relationship ID of the first slide, and then gets the slide part from the relationship ID.

// Get the relationship ID of the first slide.
PresentationPart part = ppt.PresentationPart;
OpenXmlElementList slideIds = part.Presentation.SlideIdList.ChildElements;

string relId = (slideIds[index] as SlideId).RelationshipId;

// Get the slide part from the relationship ID.
SlidePart slide = (SlidePart) part.GetPartById(relId);

' Get the relationship ID of the first slide.
Dim part As PresentationPart = ppt.PresentationPart
Dim slideIds As OpenXmlElementList = part.Presentation.SlideIdList.ChildElements

Dim relId As String = TryCast(slideIds(index), SlideId).RelationshipId

' Get the slide part from the relationship ID.
Dim slide As SlidePart = DirectCast(part.GetPartById(relId), SlidePart)

The code then declares a StringBuilder object to store the inner text of the slide. It then goes through all the slides and appends the text in each one to the StringBuilder object.

// 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();

' Build a StringBuilder object.
Dim paragraphText As New StringBuilder()

' Get the inner text of the slide:
Dim texts As IEnumerable(Of A.Text) = slide.Slide.Descendants(Of A.Text)()
For Each text As A.Text In texts
    paragraphText.Append(text.Text)
Next
sldText = paragraphText.ToString()

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();

Console.Write("Please enter a presentation file name without extension: ")
Dim fileName As String = System.Console.ReadLine()
Dim file As String = "C:\Users\Public\Documents\" + fileName + ".pptx"
Dim numberOfSlides As Integer = CountSlides(file)
System.Console.WriteLine("Number of slides = {0}", numberOfSlides)
Dim slideText As String = Nothing
For i As Integer = 0 To numberOfSlides - 1
    GetSlideIdAndText(slideText, file, i)
    System.Console.WriteLine("Slide #{0} contains: {1}", i + 1, slideText)
Next
System.Console.ReadKey()

The following is the complete sample code in both C# and Visual Basic.

public 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 CountSlides(presentationDocument);
    }
}

// Count the slides in the presentation.
public static int CountSlides(PresentationDocument presentationDocument)
{
    // Check for a null document object.
    if (presentationDocument == 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 != null)
    {
        slidesCount = presentationPart.SlideParts.Count();
    }
    // Return the slide count to the previous method.
    return slidesCount;
}

public 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;

        string relId = (slideIds[index] as SlideId).RelationshipId;

        // 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();
    }              
}

Public Function CountSlides(ByVal presentationFile As String) As Integer
    ' Open the presentation as read-only.
    Using presentationDocument__1 As PresentationDocument = PresentationDocument.Open(presentationFile, False)
        ' Pass the presentation to the next CountSlides method
        ' and return the slide count.
        Return CountSlides(presentationDocument__1)
    End Using
End Function

' Count the slides in the presentation.
Public Function CountSlides(ByVal presentationDocument As PresentationDocument) As Integer
    ' Check for a null document object.
    If presentationDocument Is Nothing Then
        Throw New ArgumentNullException("presentationDocument")
    End If

    Dim slidesCount As Integer = 0

    ' Get the presentation part of document.
    Dim presentationPart As PresentationPart = presentationDocument.PresentationPart
    ' Get the slide count from the SlideParts.
    If presentationPart IsNot Nothing Then
        slidesCount = presentationPart.SlideParts.Count()
    End If
    ' Return the slide count to the previous method.
    Return slidesCount
End Function

Public Sub GetSlideIdAndText(ByRef sldText As String, ByVal docName As String, ByVal index As Integer)
    Using ppt As PresentationDocument = PresentationDocument.Open(docName, False)
        ' Get the relationship ID of the first slide.
        Dim part As PresentationPart = ppt.PresentationPart
        Dim slideIds As OpenXmlElementList = part.Presentation.SlideIdList.ChildElements

        Dim relId As String = TryCast(slideIds(index), SlideId).RelationshipId

        ' Get the slide part from the relationship ID.
        Dim slide As SlidePart = DirectCast(part.GetPartById(relId), SlidePart)
        ' Build a StringBuilder object.
        Dim paragraphText As New StringBuilder()

        ' Get the inner text of the slide:
        Dim texts As IEnumerable(Of A.Text) = slide.Slide.Descendants(Of A.Text)()
        For Each text As A.Text In texts
            paragraphText.Append(text.Text)
        Next
        sldText = paragraphText.ToString()
    End Using
End Sub

See Also

Reference

Class Library Reference