Workbook.ExportToPdfAsync(Stream, PdfExportOptions, CancellationToken, IProgress<Int32>) Method

Asynchronously exports the workbook to a stream in PDF format. Allows you to specify export options, implement progress notifications, and cancel the operation.

You need a license for the DevExpress Office File API Subscription or DevExpress Universal Subscription to use this method in production code.

Namespace: DevExpress.Spreadsheet

Assembly: DevExpress.Docs.v23.2.dll

NuGet Package: DevExpress.Document.Processor

Declaration

C#

public Task ExportToPdfAsync(
    Stream stream,
    PdfExportOptions options,
    CancellationToken cancellationToken,
    IProgress<int> progress
)

VB.NET

Public Function ExportToPdfAsync(
    stream As Stream,
    options As PdfExportOptions,
    cancellationToken As CancellationToken,
    progress As IProgress(Of Integer)
) As Task

Parameters

Name	Type	Description
stream	Stream	Specifies the output stream.
options	PdfExportOptions	Defines export options.
cancellationToken	CancellationToken	A cancellation token that indicates whether to cancel the operation.
progress	IProgress<Int32>	An object used to report the task progress in percentage. Use a Progress<T> class instance to report progress.

Returns

Type	Description
Task	An object that defines the asynchronous export operation.

Remarks

Important

Take into account the following when you call this method:

• The events fired by this method call may occur in a different thread than the target operation.

• The operation is not thread safe (the document should not be accessed simultaneously by different threads). Wait until the operation is completed before you continue to work with the document (for example, use the await operator).

Example: Report Progress of Workbook Operations

The following example asynchronously loads and exports a workbook to PDF. The console window displays the progress of each operation. If the load or export operation takes longer than 30 seconds, it is canceled.

C#

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using DevExpress.Spreadsheet;
using DevExpress.XtraPrinting;
// ...

static async Task Main(string[] args) {
    var cancellationSource = new CancellationTokenSource(TimeSpan.FromSeconds(30));
    var cancellationToken = cancellationSource.Token;
    try {
        using (Workbook workbook = new Workbook()) {
            Console.WriteLine("Loading a document...");
            using (FileStream docStream = new FileStream("Document.xlsx", FileMode.Open))
            {
                await workbook.LoadDocumentAsync(docStream, DocumentFormat.Xlsx,
                cancellationToken,
                new Progress<int>((progress) => Console.WriteLine($"{progress}%")));
            }
            Console.WriteLine("Exporting to PDF...");
            // Specify PDF export options.
            var pdfOptions = new PdfExportOptions()
            {
                ConvertImagesToJpeg = true,
                ImageQuality = PdfJpegImageQuality.Low
            };
            using (FileStream pdfStream = new FileStream("Result.pdf", FileMode.Create))
            {
                await workbook.ExportToPdfAsync(pdfStream, pdfOptions,
                    cancellationToken,
                    new Progress<int>((progress) => Console.WriteLine($"{progress}%")));
            }
            Console.WriteLine("Done!");
        }
    }
    catch (OperationCanceledException) {
        Console.WriteLine("Cancelled by timeout.");
    }
    finally {
        cancellationSource.Dispose();
    }
}

VB.NET

Imports System
Imports System.IO
Imports System.Threading
Imports System.Threading.Tasks
Imports DevExpress.Spreadsheet
Imports DevExpress.XtraPrinting

Module Example
    Sub Main()
        MainAsync().Wait()
    End Sub
    Async Function MainAsync() As Task
        Dim cancellationSource As New CancellationTokenSource(TimeSpan.FromSeconds(30))
        Dim cancellationToken As CancellationToken = cancellationSource.Token
        Try
            Using workbook As New Workbook()
                Console.WriteLine("Loading a document...")
                Using docStream As New FileStream("Document.xlsx", FileMode.Open)
                    Await workbook.LoadDocumentAsync(docStream, DocumentFormat.Xlsx, 
                        cancellationToken, 
                        New Progress(Of Integer)(Sub(progress) Console.WriteLine($"{progress}%")))
                End Using
                Console.WriteLine("Exporting to PDF...")
                ' Specify PDF export options.
                Dim pdfOptions As New PdfExportOptions() With {
                    .ConvertImagesToJpeg = True,
                    .ImageQuality = PdfJpegImageQuality.Low
                }
                Using pdfStream As New FileStream("Result.pdf", FileMode.Create)
                    Await workbook.ExportToPdfAsync(pdfStream, pdfOptions,
                        cancellationToken, 
                        New Progress(Of Integer)(Sub(progress) Console.WriteLine($"{progress}%")))
                End Using
                Console.WriteLine("Done!")
            End Using
        Catch e1 As OperationCanceledException
            Console.WriteLine("Cancelled by timeout.")
        Finally
            cancellationSource.Dispose()
        End Try
    End Function
End Module

Calculate Formulas Before Export

The default calculation mode for a Workbook is Manual. This mode implies that the Spreadsheet does not recalculate formulas before it generates a PDF document. Call the Workbook.Calculate or Workbook.CalculateFull method to calculate all formulas in the workbook before you export it to PDF.