Classify a document

This sample demonstrates how to use document classifiers to accurately detect and identify documents you process within your application. Document classifiers are trained with your own data, so they're tailored to your documents. For more information on how to do the training, see build a document classifier.

To get started you'll need a Cognitive Services resource or a Form Recognizer resource. See README for prerequisites and instructions.

Creating a `DocumentAnalysisClient`

To create a new DocumentAnalysisClient you need the endpoint and credentials from your resource. In the sample below you'll use a Form Recognizer API key credential by creating an AzureKeyCredential object, that if needed, will allow you to update the API key without creating a new client.

You can set endpoint and apiKey based on an environment variable, a configuration setting, or any way that works for your application.

string endpoint = "<endpoint>";
string apiKey = "<apiKey>";
var credential = new AzureKeyCredential(apiKey);
var client = new DocumentAnalysisClient(new Uri(endpoint), credential);

Classify a document from a URI

To classify a given file at a URI, use the ClassifyDocumentFromUri method. The returned value is an AnalyzeResult object containing data about the submitted document.

string classifierId = "<classifierId>";
Uri fileUri = new Uri("<fileUri>");

ClassifyDocumentOperation operation = await client.ClassifyDocumentFromUriAsync(WaitUntil.Completed, classifierId, fileUri);
AnalyzeResult result = operation.Value;

Console.WriteLine($"Document was classified by classifier with ID: {result.ModelId}");

foreach (AnalyzedDocument document in result.Documents)
{
    Console.WriteLine($"Document of type: {document.DocumentType}");
}

Classify a document from a file stream

To classify a given file at a file stream, use the ClassifyDocument method. The returned value is an AnalyzeResult object containing data about the submitted document.

string classifierId = "<classifierId>";
string filePath = "<filePath>";

using var stream = new FileStream(filePath, FileMode.Open);

ClassifyDocumentOperation operation = await client.ClassifyDocumentAsync(WaitUntil.Completed, classifierId, stream);
AnalyzeResult result = operation.Value;

Console.WriteLine($"Document was classified by classifier with ID: {result.ModelId}");

foreach (AnalyzedDocument document in result.Documents)
{
    Console.WriteLine($"Document of type: {document.DocumentType}");
}