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The fluent API composes a conversion as a single chained expression. It’s implemented by the FluentConverter class and the staged interfaces in the GroupDocs.Conversion.Fluent namespace — each call returns a new stage interface that exposes only the methods valid for the next step.
A fluent chain moves through four stages:
| Stage | Purpose | Methods |
|---|---|---|
| Entry | Configure the converter before any source is opened | WithSettings(...), WithEvents(...) |
| Load | Specify the source and (optionally) load options | Load(...), WithOptions(LoadOptions) |
| Convert | Specify the target and conversion options | ConvertTo(...), ConvertByPageTo(...), WithOptions(ConvertOptions), Compress(...) |
| Terminal | Execute the operation | Convert(), GetDocumentInfo(), GetPossibleConversions() |
Entry-stage calls are optional; the shortest valid chain skips straight to Load(...).
The minimal chain — load a file, name the target, run:
FluentConverter
.Load("sample.docx")
.ConvertTo("converted.pdf")
.Convert();
Add load and convert options when you need them:
FluentConverter
.Load("sample.pdf").WithOptions(new PdfLoadOptions())
.ConvertTo("converted.docx").WithOptions(new WordProcessingConvertOptions())
.Convert();
Use WithSettings(...) to customize the ConverterSettings — for example, to set a logger or cache:
FluentConverter
.WithSettings(() => new ConverterSettings { Logger = new ConsoleLogger() })
.Load("sample.docx")
.ConvertTo("converted.pdf")
.Convert();
Use WithEvents(...) to register handlers on the ConversionEvents aggregator — see Subscribing to conversion events below.
Both entry-stage calls are optional and can be combined in either order:
FluentConverter
.WithSettings(() => new ConverterSettings { Logger = new ConsoleLogger() })
.WithEvents(e => e.OnDocumentConverted = ctx => Console.WriteLine($"Done: {ctx.SourceFileName}"))
.Load("sample.docx")
.ConvertTo("converted.pdf")
.Convert();
Use ConvertByPageTo(...) to write each source page to its own stream:
FluentConverter
.Load("sample.pdf").WithOptions(new PdfLoadOptions())
.ConvertByPageTo((SavePageContext ctx) => new FileStream($"converted-{ctx.Page}.docx", FileMode.Create))
.WithOptions(new WordProcessingConvertOptions())
.Convert();
The stream factory receives a SavePageContext with the page number and source format — return a fresh stream for each call.
Two terminal methods replace Convert() when you need information about the source rather than a converted output:
// Available target formats for this source
PossibleConversions possible = FluentConverter
.Load("sample.pdf")
.GetPossibleConversions();
// Format-specific metadata (page count, properties, etc.)
IDocumentInfo info = FluentConverter
.Load("sample.pdf")
.GetDocumentInfo();
Both accept a load-options stage if the source needs one:
FluentConverter.Load("sample.pdf").WithOptions(new PdfLoadOptions()).GetPossibleConversions();
FluentConverter.Load("sample.pdf").WithOptions(new PdfLoadOptions()).GetDocumentInfo();
Convert() accepts a CancellationToken for timeout or user-driven cancellation — see Cancellation for the full pattern:
using var cts = new CancellationTokenSource();
cts.CancelAfter(TimeSpan.FromSeconds(60));
FluentConverter
.Load("sample.dwg")
.ConvertTo("converted.pdf").WithOptions(new PdfConvertOptions())
.Convert(cts.Token);
Since version 26.6, event handlers are registered through the ConversionEvents aggregator via the entry-stage WithEvents(...) method. The aggregator covers both pipeline lifecycle events (OnConversionStarted / OnConversionProgress / OnConversionCompleted) and per-result events (OnDocumentConverted / OnDocumentFailed / OnPageConverted / OnPageFailed / OnCompressionCompleted):
FluentConverter
.WithEvents(e =>
{
e.OnConversionStarted = () => Console.WriteLine("Conversion started");
e.OnConversionProgress = percent => Console.WriteLine($"... {percent}% ...");
e.OnDocumentConverted = ctx => Console.WriteLine($"Done: {ctx.SourceFileName}");
e.OnDocumentFailed = (ctx, ex) => Console.WriteLine($"Failed: {ex.Message}");
e.OnPageFailed = (ctx, ex) => Console.WriteLine($"Page failed: {ex.Message}");
})
.Load("sample.docx")
.ConvertTo("converted.pdf").WithOptions(new PdfConvertOptions())
.Convert();
The .OnConversionCompleted(...) and .OnConversionFailed(...) handlers placed after WithOptions(...) remain supported. The late-stage .OnCompressionCompleted(...) placed after .Compress(...) was removed in version 26.9 — register it with WithEvents(e => e.OnCompressionCompleted = ...) instead. See the Conversion events guide for the full migration story, including the rename of per-result handlers from OnConversion* to OnDocument* / OnPage*.
- Conversion events — full reference for
WithEvents(...)andConversionEvents - Context Objects — Complete Guide — properties exposed by
SaveContext,SavePageContext,ConvertedContext, etc. - Cancellation — passing a
CancellationTokenthrough the fluent chain - Extract and Convert Archive Contents —
Compress(...)andOnCompressionCompleted
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