Document Content Modification

• Jul 18, 2024
• 5 minutes to read

A PDF document contains content customization API that allows you to do the following:

• Add, delete, and rearrange Pages.
• Append a separate document and thus merge two PDF files into one.
• Manage file FileAttachments.

Every document change raises the OnChanged event. Enclose multiple structure changes between BeginUpdate and EndUpdate calls to avoid excessive change notifications.

Append Documents

You can merge multiple documents into one. Call a PDF document container’s Append procedure to append all pages, attachments, and bookmarks from a specified document to the current document.

The following code example invokes the Open dialog to load a PDF document and append it to the “Demo.pdf” document file:

Delphi

var
  ADocument: TdxPDFDocument;
  ASource: TdxPDFDocument;
begin
  if OpenDialog.Execute then
  begin
    ADocument := TdxPDFDocument.Create;
    ASource := TdxPDFDocument.Create;
    try
      ADocument.LoadFromFile('Data\Demo.pdf');
      ASource.LoadFromFile(OpenDialog.FileName);
      ADocument.Append(ASource);
      ADocument.SaveToFile('Data\Result.pdf');
    finally
      ADocument.Free;
      ASource.Free;
    end;
  end;
end; 

C++

  TdxPDFDocument *ADocument;
  TdxPDFDocument *ASource;
  if (OpenDialog->Execute())
  {
      ADocument = new TdxPDFDocument();
    ASource = new TdxPDFDocument();
      try
      {
        ADocument->LoadFromFile("Data\\Demo.pdf");
      ASource->LoadFromFile(OpenDialog->FileName);
        ADocument->Append(ASource);
      ADocument->SaveToFile("Data\\Result.pdf");
      }
      __finally
      {
      delete ADocument;
      delete ASource;
      }
  }

Manage Pages

Add Pages

Call the Pages.Add or Pages.Insert procedure to append or insert pages from a source document into the current document. These operations ignore attachments and bookmarks in the source document. If you need to merge multiple documents including attachments and bookmarks, call the Append procedure instead.

The following code example inserts the first two pages from a source document after the first page in the “Demo.pdf” document file:

Delphi

var
  ADocument: TdxPDFDocument;
  ASource: TdxPDFDocument;
begin
  ADocument := TdxPDFDocument.Create;
  ASource := TdxPDFDocument.Create;
  try
    ADocument.LoadFromFile('Data\Demo.pdf');
    ASource.LoadFromFile('Data\Source.pdf');

    ADocument.BeginUpdate;
    try
      // Inserts the first page (0) from the source document as the second page (1) in the current document
      ADocument.Pages.Insert(1, ASource, 0);
      // Inserts the second page (1) from the source document as the third page (2) in the current document
      ADocument.Pages.Insert(2, ASource, 1);
    finally
      ADocument.EndUpdate;
    end;
    ADocument.SaveToFile('Data\Result.pdf');
  finally
    ADocument.Free;
    ASource.Free;
  end;

C++

  TdxPDFDocument *ADocument = new TdxPDFDocument();
  TdxPDFDocument *ASource = new TdxPDFDocument();
  try
  {
    ADocument->LoadFromFile("Data\\Demo.pdf");
    ADocument->LoadFromFile("Data\\Source.pdf");

    ADocument->BeginUpdate();
    try
    {
      // Inserts the first page (0) from the source document as the second page (1) in the current document
      ADocument->Pages->Insert(1, ASource, 0);
      // Inserts the second page (1) from the source document as the third page (2) in the current document
      ADocument->Pages->Insert(2, ASource, 1);
    }
    __finally
    {
      ADocument->EndUpdate();
    }
    ADocument->SaveToFile("Data\\Result.pdf");
  }
  __finally
  {
    delete ADocument;
    delete ASource;
  }

Rearrange Pages

Call the Pages.Move procedure to move pages within the same document.

The following code example swaps the first and second pages in the Demo.pdf document:

Delphi

var
  ADocument: TdxPDFDocument;
begin
  ADocument := TdxPDFDocument.Create;
  try
    ADocument.LoadFromFile('Data\Demo.pdf');
    ADocument.Pages.Move(0, 1);

    ADocument.SaveToFile('Data\Result.pdf');
  finally
    ADocument.Free;
  end; 

C++

  TdxPDFDocument *ADocument = new TdxPDFDocument();
  try
  {
    ADocument->LoadFromFile("Data\\Demo.pdf");
    ADocument->Pages->Move(0, 1);

    ADocument->SaveToFile("Data\\Result.pdf");
  }
  __finally
  {
    delete ADocument;
  }

Delete Pages

Call the Pages.Delete procedure to delete a page.

The following code example loads a PDF document from the Demo.pdf file, deletes the first two pages of the loaded document, and saves the resulting document to a different file (Result.pdf):

Delphi

uses
  dxPDFDocument;  // This unit declares the TdxPDFDocument class
// ...
var
  ADocument: TdxPDFDocument;
begin
  ADocument := TdxPDFDocument.Create;
  try
    ADocument.LoadFromFile('Data\Demo.pdf');
    ADocument.BeginUpdate;  // Initiates the following batch change
    try
      ADocument.Pages.Delete(0);
      ADocument.Pages.Delete(0);
    finally
      ADocument.EndUpdate;  // Calls EndUpdate regardless of the batch operation's success
    end;
    ADocument.SaveToFile('Data\Result.pdf');
  finally
    ADocument.Free;  // Releases the created document container to avoid memory leaks
  end;

C++

#include "dxPDFDocument.hpp"  // This header declares the TdxPDFDocument class
// ...
  TdxPDFDocument *ADocument = new TdxPDFDocument();
  try
  {
    ADocument->LoadFromFile("Data\\Demo.pdf");
    ADocument->BeginUpdate();  // Initiates the following batch change
    try
    {
      ADocument->Pages->Delete(0);
      ADocument->Pages->Delete(0);
    }
    __finally
    {
      ADocument->EndUpdate();  // Calls EndUpdate regardless of the batch operation's success
    }
    ADocument->SaveToFile("Data\\Result.pdf");
  }
  __finally
  {
    delete ADocument;  // Releases the created document container to avoid memory leaks
  }

Batch Operations

Call the following overloaded procedures available in a PDF document container and pass an array of page indexes as a parameter to perform batch page management operations:

• Pages.Add
• Pages.Delete
• Pages.Insert
• Pages.Move

Manage File Attachments

Add Attachments

Call the FileAttachments.Add function to create a new empty attachment. Then, call the attachment’s LoadFromFile or LoadFromStream procedure to load content.

The following code example invokes the Open dialog to load a file and attach it to the “Demo.pdf” document:

Delphi

var
  ADocument: TdxPDFDocument;
  AAttachment: TdxPDFFileAttachment;
begin
  if OpenDialog.Execute then
  begin
    ADocument := TdxPDFDocument.Create;
    try
      ADocument.LoadFromFile('Data\Demo.pdf');
      ADocument.BeginUpdate;
      try
        AAttachment := ADocument.FileAttachments.Add;
        AAttachment.LoadFromFile(OpenDialog.FileName);
      finally
        ADocument.EndUpdate;
      end;
      ADocument.SaveToFile('Data\Result.pdf');
    finally
      ADocument.Free;
    end;
  end;
end;

C++

  TdxPDFDocument *ADocument;
  TdxPDFFileAttachment *AAttachment;
  //...
  if(OpenDialog->Execute())
  {
      ADocument = new TdxPDFDocument();
      try
      {
        ADocument->LoadFromFile("Data\\Demo.pdf");
        ADocument->BeginUpdate();
        try
        {
          AAttachment = ADocument->FileAttachments->Add();
          AAttachment->LoadFromFile(OpenDialog->FileName);
        }
        __finally
        {
          ADocument->EndUpdate();
        }
      ADocument->SaveToFile("Data\\Result.pdf");
      }
      __finally
      {
        delete ADocument;
      }
  }

Remove Attachments

Call the FileAttachments.Remove function to remove a file attachment.

The following procedure loads the “Demo.pdf” file and removes file attachments whose names match the parameter value.

Delphi

procedure TfrmPDFFileAttachment.Remove(const AFileName: string);
var
  ADocument: TdxPDFDocument;
  AAttachment: TdxPDFFileAttachment;
begin
  ADocument := TdxPDFDocument.Create;
  try
    ADocument.LoadFromFile('Data\Demo.pdf');
    for AAttachment in ADocument.FileAttachments do
      if SameText(AAttachment.FileName, AFileName) then
        ADocument.FileAttachments.Remove(AAttachment)
    ADocument.SaveToFile('Data\Result.pdf');
  finally
    ADocument.Free;
  end;
end;

C++

void TfrmPDFFileAttachment::Remove(const UnicodeString AFileName)
{
  TdxPDFDocument *ADocument;
  TdxPDFFileAttachment *AAttachment;
  //...
  ADocument = new TdxPDFDocument();
  try
  {
    ADocument->LoadFromFile("Data\\Demo.pdf");
    for (int I = 0; I < dxPDFViewer1->Document->FileAttachments->Count; I++) {
      if (SameText(ADocument->FileAttachments->Items[I]->FileName, AFileName))
        ADocument->FileAttachments->Remove(ADocument->FileAttachments->Items[I]);
    }
    ADocument.SaveToFile("Data\\Result.pdf");
  }
  __finally
  {
    delete ADocument;
  }
}