Convert Multiple Presentations

Convert mixed valid, corrupt and encrypted presentations sequentially and with at most two independent workers.

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/batch-conversion/block-001");
        await 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.successes_per_run\":3,\"checks.failures_per_run\":2,\"checks.unique_outputs\":true,\"checks.worker_limits_observed\":true,\"checks.later_jobs_processed\":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/batch-conversion/block-001",checks);
        await Task.CompletedTask;
    });


    private sealed record JobResult(string Source,string Output,bool Success,string? Error);
    private static async Task<(JobResult[] Results,int Peak)> ConvertAll(string[] files,string directory,int workerLimit)
    {
        Directory.CreateDirectory(directory);var results=new ConcurrentBag<JobResult>();int active=0,peak=0;
        await Parallel.ForEachAsync(files,new ParallelOptions{MaxDegreeOfParallelism=workerLimit},(path,cancellation)=>
        {
            int current=Interlocked.Increment(ref active);int observed;
            do{observed=Volatile.Read(ref peak);if(current<=observed)break;}while(Interlocked.CompareExchange(ref peak,current,observed)!=observed);
            string identity=Example.Hash(Encoding.UTF8.GetBytes(Path.GetRelativePath("output/inputs",path)))[..12];
            string destination=Path.Combine(directory,Path.GetFileNameWithoutExtension(path)+"-"+identity+".pdf");
            try
            {using var p=new Presentation(path,new LoadOptions{LoadFormat=LoadFormat.Pptx});p.Save(destination,SaveFormat.Pdf);Example.Require(File.ReadAllBytes(destination).Take(5).SequenceEqual(Encoding.ASCII.GetBytes("%PDF-")),"Invalid PDF header.");results.Add(new(path,destination,true,null));}
            catch(Exception ex){if(File.Exists(destination))File.Delete(destination);results.Add(new(path,destination,false,ex.GetType().Name+": "+ex.Message));}
            finally{Interlocked.Decrement(ref active);}return ValueTask.CompletedTask;
        });
        return(results.OrderBy(r=>r.Source,StringComparer.Ordinal).ToArray(),peak);
    }
    private static async Task RunExample()
    {
        Example.Setup();Directory.CreateDirectory("output/inputs/a");Directory.CreateDirectory("output/inputs/b");
        foreach(var item in new[]{("a/shared.pptx","North"),("b/shared.pptx","South"),("later.pptx","Processed after failures")})
        {using var p=new Presentation();Example.Text(p.Slides[0].Shapes,"Text",item.Item2);p.Save("output/inputs/"+item.Item1,SaveFormat.Pptx);}
        File.WriteAllBytes("output/inputs/corrupt.pptx",new byte[]{0x50,0x4b,3,4,0,0,0});
        using(var p=new Presentation()){p.ProtectionManager.Encrypt("SyntheticExamplePassword");p.Save("output/inputs/locked.pptx",SaveFormat.Pptx);}
        string[] files=Directory.GetFiles("output/inputs","*.pptx",SearchOption.AllDirectories).OrderBy(p=>p,StringComparer.Ordinal).ToArray();
        var sequential=await ConvertAll(files,"output/sequential",1);var parallel=await ConvertAll(files,"output/parallel",2);
        foreach(var result in new[]{sequential,parallel})
        {Example.Require(result.Results.Count(r=>r.Success)==3&&result.Results.Count(r=>!r.Success)==2,"File outcomes differ.");Example.Require(result.Results.Where(r=>r.Success).Select(r=>r.Output).Distinct().Count()==3,"Output filenames collide.");Example.Require(result.Results.Single(r=>r.Source.EndsWith("later.pptx")).Success,"Later job did not run.");}
        Example.Require(sequential.Peak<=1&&parallel.Peak<=2,"Worker limit exceeded.");
        Example.Json("output/results.json",new{sequential=sequential.Results,parallel=parallel.Results,sequential_peak=sequential.Peak,parallel_peak=parallel.Peak});
        Example.Result(new{successes_per_run=3,failures_per_run=2,unique_outputs=true,worker_limits_observed=true,later_jobs_processed=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:

{
  "successes_per_run": 3,
  "failures_per_run": 2,
  "unique_outputs": true,
  "worker_limits_observed": true,
  "later_jobs_processed": true
}

The worker loop, filename policy and result manifest belong to the application. Each worker owns its Presentation instance; no mutable presentation is shared. Source-relative identity hashes distinguish equal basenames. Per-file failures are retained and processing continues. Two workers is an example limit, not a universal memory recommendation. Initialize licensing before starting workers.

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.

Process Presentations with Large Media Track Progress and Cancel Processing