Track Progress and Cancel Processing

Observe PDF export progress, request an SDK interruption during another export, and confirm that the operation stops before completion.

Run the example

Download the complete project, extract it, and run it with the .NET 8 SDK. The project pins Aspose.Slides.NET6.CrossPlatform 26.10.0. The complete project uses portable image fixtures and the CrossPlatform package. For the complete data assertions, set ASPOSE_LICENSE_PATH to your own valid license; the visible helper loads it when supplied. Evaluation mode may truncate text or add watermarks.

dotnet restore Example.csproj 
dotnet run --project Example.csproj --configuration Release --no-restore

The download contains Program.cs, Example.cs, the project, dependency lock, and any JSON/CSV input. The helper source contains fixture generation, license loading, serialization and assertions; it is part of the runnable project. All presentation inputs are generated from original synthetic data. Results go to output/.

Example

using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using System.Drawing;
using System.Globalization;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Text;
using System.Text.Json;
using Aspose.Slides;
using Aspose.Slides.Charts;
using Aspose.Slides.DOM.Ole;
using Aspose.Slides.Export;
using Aspose.Slides.LowCode;
using Aspose.Slides.Warnings;

internal static class Program
{
    private static ExampleContext Context = null!;
    private static Task<int> Main(string[] args) => ExampleBootstrap.RunAsync(args, async ctx =>
    {
        Context = ctx;
        Example.Context = ctx;
        ctx.BeginAction("optimization-batch/progress-cancellation/block-001");
        RunExample();
        string path=File.Exists("output/result.json")?"output/result.json":"result.json";
        using var result=JsonDocument.Parse(File.ReadAllText(path));
        var checks=new System.Collections.Generic.Dictionary<string,bool>();
        if(ctx.IsLicensed)
        {
            using var expected=JsonDocument.Parse("{\"checks.progress_observed\":true,\"checks.cancellation_requested\":true,\"checks.operation_stopped\":true,\"checks.partial_output_removed\":true,\"checks.input_unlocked\":true}");
            foreach(var field in expected.RootElement.EnumerateObject())
            {
                var actual=result.RootElement;foreach(string part in field.Name.Split('.'))actual=actual.GetProperty(part);
                ctx.Require(actual.ToString()==field.Value.ToString(),"Licensed assertion differs: "+field.Name);
                checks["licensed-"+field.Name.Replace('.','-')]=true;
            }
        }
        else
        {
            var values=result.RootElement.TryGetProperty("checks",out var nested)?nested:result.RootElement;
            foreach(var field in values.EnumerateObject())if(field.Value.ValueKind==JsonValueKind.False)throw new InvalidOperationException("Evaluation assertion failed: "+field.Name);
            checks["evaluation-semantic-effect"]=true;checks["evaluation-valid-output"]=true;
        }
        foreach(string pdf in Directory.GetFiles(".","*.pdf",SearchOption.AllDirectories))ctx.Require(File.ReadAllBytes(pdf).AsSpan(0,5).SequenceEqual(System.Text.Encoding.ASCII.GetBytes("%PDF-")),"Invalid PDF output.");
        foreach(string png in Directory.GetFiles(".","*.png",SearchOption.AllDirectories)){var image=PortableImage.Decode(File.ReadAllBytes(png));ctx.Require(image.Width>0&&image.Height>0,"Empty PNG output.");}
        ctx.Pass("optimization-batch/progress-cancellation/block-001",checks);
        await Task.CompletedTask;
    });


    private sealed class Progress : IProgressCallback
    {
        public List<double> Values {get;}=new();private readonly InterruptionTokenSource? _source;public bool Requested{get;private set;}
        public Progress(InterruptionTokenSource? source=null){_source=source;}
        public void Reporting(double value){Values.Add(value);if(_source!=null&&!Requested&&value>0){Requested=true;_source.Interrupt();}}
    }
    private static void RunExample()
    {
        Example.Setup();using(var p=new Presentation())
        {for(int i=0;i<24;i++){var slide=i==0?p.Slides[0]:p.Slides.AddEmptySlide(p.LayoutSlides[0]);Example.Text(slide.Shapes,"Title","Slide "+(i+1));Example.ChartData(Example.Chart(slide,"Chart"),new[]{"A","B","C"},new[]{"Series"},new[]{new[]{1.0,2.0,3.0}});}p.Save("output/input.pptx",SaveFormat.Pptx);}
        var fullProgress=new Progress();using(var p=new Presentation("output/input.pptx")){p.Save("output/complete.pdf",SaveFormat.Pdf,new PdfOptions{ProgressCallback=fullProgress});}
        Example.Require(fullProgress.Values.Count>0&&fullProgress.Values.Max()==100,"Full PDF export did not report completion.");
        var source=new InterruptionTokenSource();var cancellationProgress=new Progress(source);bool exceptionObserved=false;
        try{using var p=new Presentation("output/input.pptx",new LoadOptions{InterruptionToken=source.Token});p.Save("output/partial.pdf",SaveFormat.Pdf,new PdfOptions{ProgressCallback=cancellationProgress});}
        catch(OperationCanceledException){exceptionObserved=true;}
        finally{if(File.Exists("output/partial.pdf"))File.Delete("output/partial.pdf");}
        using(var exclusive=File.Open("output/input.pptx",FileMode.Open,FileAccess.ReadWrite,FileShare.None)){}
        // Some library export paths return normally after an interruption. Compare
        // their progress against the successful control, rather than requiring an exception.
        bool stopped=exceptionObserved||(cancellationProgress.Requested&&cancellationProgress.Values.Count>0&&cancellationProgress.Values.Max()<100);
        Example.Require(cancellationProgress.Requested&&stopped,"Cancellation request did not stop the SDK operation before completion.");
        Example.Require(!File.Exists("output/partial.pdf"),"Partial output was retained.");
        Example.Json("output/progress.json",new{complete=fullProgress.Values,cancelled=cancellationProgress.Values,cancellation_requested=cancellationProgress.Requested,operation_stopped=stopped,operation_canceled_exception=exceptionObserved});
        Example.Result(new{progress_observed=true,cancellation_requested=true,operation_stopped=true,partial_output_removed=true,input_unlocked=true});
    }

}

Expected result and checks

The program writes its semantic checks to output/result.json and throws if a required result differs. Expected check values are:

{
  "progress_observed": true,
  "cancellation_requested": true,
  "operation_stopped": true,
  "partial_output_removed": true,
  "input_unlocked": true
}

The control export must reach 100 percent. A second progress callback requests interruption after work begins; the sample requires either OperationCanceledException or observed progress stopping below 100 percent. Some export paths return normally after interruption, so a request or normal return alone is not treated as success. Partial output is removed, the source can be opened exclusively after disposal, and the completed control PDF remains available. Callback frequency is operation-dependent.

Learn more

Open and run the complete project

Download the complete project, extract it and open Example.sln, or run:

dotnet restore Example.sln
dotnet run --project Example.csproj --configuration Release -- --mode evaluation

Use the current supported .NET 10 SDK/runtime. The project keeps a stable net8.0 target and accepts compatible stable SDKs; no exact SDK patch is required. Evaluation runs without a license and explicitly ignores license environment settings. It uses bounded fixtures and checks valid output while allowing the evaluation watermark and documented read-back text truncation. For unrestricted checks, use --mode licensed with your authorized ASPOSE_LICENSE_PATH. No license is included.

Inputs are copied from Fixtures into a separate output workspace. The program prints the absolute output path; execution.json records the actual runtime and verified action. The portable PNG helper creates original synthetic pixels without a Windows bitmap engine. See setup and prerequisites for native libraries, fonts, IDE settings and the .NET 8/9 runtime support boundary of 2026-11-10.

Convert Multiple Presentations Collect Rendering and Export Warnings