| title | Working with Recognize methods in SmartFormRecognizer| Syncfusion® |
|---|---|
| description | Learn how to effectively use the Recognize methods in the Syncfusion® SmartFormRecognizer library to process and detects from forms with ease. |
| platform | document-processing |
| control | SmartFormRecognizer |
| documentation | UG |
The FormRecognizer exposes several convenience methods to recognize forms from a Stream input. Each method accepts an input Stream (PDF or image) and returns recognized output either as a PdfLoadedDocument, a Stream containing PDF data, or as a JSON string.
Below each method signature you'll find a explanation and corrected example usage (both synchronous and asynchronous where applicable).
Using PdfLoadedDocument this operation analyzes the form content supplied through the inputStream whether it contains a PDF or an image and produces a fully enriched PdfLoadedDocument that includes recognized form elements such as checkboxes, radio buttons, textboxes, and signatures, according to the options defined in FormRecognizeOptions. This recognition process supports both execution patterns: the synchronous RecognizeFormAsPdfDocument method for immediate, blocking processing, and the asynchronous RecognizeFormAsPdfDocumentAsync method for non‑blocking, await processing ideal for responsive UI applications or scalable server side workflows.
Example (synchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream PdfLoadedDocument pdfLoadedDocument = smartFormRecognizer.RecognizeFormAsPdfDocument(inputStream); //Save the loadeddocument pdfLoadedDocument.Save(Output.pdf); } {% endhighlight %} {% endtabs %}
Example (asynchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public async void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream PdfLoadedDocument pdfLoadedDocument = await smartFormRecognizer.RecognizeFormAsPdfDocumentAsync(inputStream); //Save the loadeddocument pdfLoadedDocument.Save(Output.pdf); }
{% endhighlight %} {% endtabs %}
Using Streamthis operation processes the form content provided through the inputStream whether it contains a PDF or an image and returns the fully recognized PDF as a Stream.This functionality is available through both the synchronous RecognizeFormAsPdfStream method for immediate, blocking execution and the asynchronous RecognizeFormAsPdfStreamAsync method for non‑blocking, await processing suitable for responsive UI applications, background services, and scalable server‑side workflows.
Example (synchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream Stream outputStream = smartFormRecognizer.RecognizeFormAsPdfStream(inputStream); //Save the output PDF stream to file using (FileStream fileStream = File.Create("Output.pdf")) { outputStream.Seek(0, SeekOrigin.Begin); outputStream.CopyTo(fileStream); } } {% endhighlight %} {% endtabs %}
Example (asynchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public async void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream Stream outputStream = await smartFormRecognizer.RecognizeFormAsPdfStreamAsync(inputStream); //Save the output PDF stream to file using (FileStream fileStream = File.Create("Output.pdf")) { outputStream.Seek(0, SeekOrigin.Begin); outputStream.CopyTo(fileStream); } }
{% endhighlight %} {% endtabs %}
Using JSONthis operation recognizes the form contained in the inputStream whether the source document is a PDF or an image and returns the complete recognition output serialized as a JSON string. This functionality is accessible through both the synchronous RecognizeFormAsJson method, which performs immediate, blocking processing, and the asynchronous RecognizeFormAsJsonAsync method, which provides non‑blocking, await execution suitable for UI applications, background workers, and scalable cloud or server‑side workflows.
Example (synchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream String outputJson = smartFormRecognizer.RecognizeFormAsJson(inputStream); //Save the outputJson File.Create("D:\result.json").Close(); File.WriteAllText("D:\result.json", outputJson); } {% endhighlight %} {% endtabs %}
Example (asynchronous):
{% tabs %} {% highlight c# tabtitle="C#" %} public async void Button_Click(object sender, RoutedEventArgs e) { //Initialize the Form Recognizer FormRecognizer smartFormRecognizer = new FormRecognizer(); //Read the input PDF file as stream FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.ReadWrite); //Recognize the form and get the output as PDF stream String outputJson = await smartFormRecognizer.RecognizeFormAsJsonAsync(inputStream); //Save the outputJson File.Create("D:\result.json").Close(); File.WriteAllText("D:\result.json", outputJson);
}
{% endhighlight %} {% endtabs %}
The async overloads accept an optional CancellationToken to cancel long running operations. Initially, the cancellationToken uses its default value, and based on our requirements, we can optimize or supply a custom token as needed. This behavior is supported across all async methods, including PDF, JSON, and PdfLoadedDocument asynchronous operations
Example with cancellation token (PDF stream):
{% tabs %} {% highlight c# tabtitle="C#" %}
public async Task RecognizeWithCancellationAsync() { FormRecognizer recognizer = new FormRecognizer();
using FileStream inputStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);
CancellationTokenSource cts = new CancellationTokenSource();
cts.CancelAfter(TimeSpan.FromSeconds(5)); // cancel in 5 seconds
CancellationToken token = cts.Token;
using Stream resultStream = await recognizer.RecognizeFormAsPdfStreamAsync(inputStream, token);
using FileStream fileStream = File.Create("Output.pdf");
await resultStream.CopyToAsync(fileStream, token);
}
{% endhighlight %} {% endtabs %}