Fill a Presentation Template

What this page is about

Fill required customer markers, including a marker split across text portions, from JSON. The sample keeps surrounding bold formatting and leaves the template unchanged.

Fill required customer markers, including a marker split across text portions, from JSON. The sample keeps surrounding bold formatting and leaves the template unchanged.

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.Threading.Tasks;
using System;
using System.Collections.Generic;
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;

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("templates-data/fill-placeholders/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.marker_replaced\":true,\"checks.format_retained\":true,\"checks.missing_required_rejected\":true,\"checks.long_text_checked\":true,\"checks.input_unchanged\":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("templates-data/fill-placeholders/block-001",checks);
        await Task.CompletedTask;
    });


    private static void Bind(ISlide slide,Dictionary<string,string> data)
    {
        if(!data.TryGetValue("Customer",out string? customer)||string.IsNullOrWhiteSpace(customer))throw new InvalidDataException("Customer is required.");
        foreach(var frame in Example.Frames(slide))
        {frame.ReplaceText("{{Customer}}",customer,new TextSearchOptions{CaseSensitive=true},null);
         frame.ReplaceText("{{Optional}}",data.GetValueOrDefault("Optional",""),new TextSearchOptions{CaseSensitive=true},null);
         frame.TextFrameFormat.AutofitType=TextAutofitType.Normal;}
        if(Example.Frames(slide).Any(f=>f.Text.Contains("{{")))throw new InvalidDataException("Unbound template marker.");
    }
    private static void RunExample()
    {
        Example.Setup();
        var values=JsonSerializer.Deserialize<Dictionary<string,string>>(File.ReadAllText("customer.json"))!;
        using(var template=new Presentation())
        {
            var title=Example.Text(template.Slides[0].Shapes,"Customer","",35,35,600,100);
            var p=title.TextFrame.Paragraphs[0];p.Portions.Clear();
            var prefix=new Portion("Customer: ");prefix.PortionFormat.FontBold=NullableBool.True;p.Portions.Add(prefix);
            p.Portions.Add(new Portion("{{Cus"));p.Portions.Add(new Portion("tomer}}"));
            foreach(var portion in p.Portions){portion.PortionFormat.LatinFont=new FontData("Noto Sans");portion.PortionFormat.FontHeight=24;portion.PortionFormat.FillFormat.FillType=FillType.Solid;portion.PortionFormat.FillFormat.SolidFillColor.Color=Color.FromArgb(35,65,100);}
            Example.Text(template.Slides[0].Shapes,"Optional","{{Optional}}",35,180,600,60);
            template.Save("output/template.pptx",SaveFormat.Pptx);
        }
        string before=Example.HashFile("output/template.pptx");
        using(var p=new Presentation("output/template.pptx"))
        {
            Bind(p.Slides[0],values);p.Save("output/filled.pptx",SaveFormat.Pptx);Example.Render(p,"output/preview.png");
        }
        using var check=new Presentation("output/filled.pptx");
        var shape=Example.Named<IAutoShape>(check.Slides[0],"Customer");
        Example.Require(shape.TextFrame.Text==Example.ExpectedText("Customer: "+values["Customer"]),"Run-spanning marker was not replaced.");
        Example.VerifySavedText("output/filled.pptx","Customer","Customer: "+values["Customer"]);
        Example.Require(shape.TextFrame.Paragraphs[0].Portions[0].PortionFormat.FontBold==NullableBool.True,"Prefix style changed.");
        bool missing=Example.Throws(()=>Bind(check.Slides[0],new Dictionary<string,string>()));
        using var longDeck=new Presentation("output/template.pptx");Bind(longDeck.Slides[0],new(){{"Customer",string.Join(" ",Enumerable.Repeat("Long customer name",8))}});
        var longShape=Example.Named<IAutoShape>(longDeck.Slides[0],"Customer");
        // Bounded application-side fitting keeps the text measurable before saving.
        longShape.TextFrame.TextFrameFormat.AutofitType=TextAutofitType.None;
        for(float size=24;size>=10;size--)
        {foreach(var paragraph in longShape.TextFrame.Paragraphs)foreach(var portion in paragraph.Portions)portion.PortionFormat.FontHeight=size;
         if(longShape.TextFrame.Paragraphs.Sum(p=>p.GetRect().Height)<=longShape.Height-12)break;}
        bool overflow=longShape.TextFrame.Paragraphs.Sum(p=>p.GetRect().Height)>longShape.Height-12;
        Example.Render(longDeck,"output/long-preview.png");Example.Require(!overflow,"Long text overflows the checked frame height.");
        Example.Require(Example.HashFile("output/template.pptx")==before,"Input changed.");
        Example.Result(new{marker_replaced=true,format_retained=true,missing_required_rejected=missing,long_text_checked=!overflow,input_unchanged=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:

{
  "marker_replaced": true,
  "format_retained": true,
  "missing_required_rejected": true,
  "long_text_checked": true,
  "input_unchanged": true
}

Required values are checked before replacement. Optional values default to empty strings. The long-name case applies a bounded font-size reduction, checks paragraph height and creates a separate preview for visual review. Mixed styles within a replaced marker need their own design decision; this example preserves the surrounding prefix.

Learn more

• Manage Presentation Placeholders in .NET
• Search and Replace Text in PowerPoint Presentations in .NET
• Enhance Your Presentations with AutoFit in .NET

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.