Import and Export Form Field

Aspose.PDF for .NET provides great capabilities for create/manipulating form fields inside PDF document. Using this API, you can programmatically fill form fields inside PDF file, fill form fields by Import Data from FDF into a PDF File, Import Data from XFDF into a PDF File, Import Data from XML into a PDF File or even you can import data from System.Data.DataTable object.

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.Pdf-for-.NET
private static void ImportData()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdfFacades_Forms();

    using (var form = new Aspose.Pdf.Facades.Form())
    {
        // Bind PDF document
        form.BindPdf(dataDir + "input.pdf");

        // Import data fdf
        using (var xfdfInputStream  = new FileStream(dataDir + "student.fdf", FileMode.Open))
        {
            form.ImportFdf(xfdfInputStream);
        }
                
        // Import data XML
        using (var xfdfInputStream  = new FileStream(dataDir + "input.xml", FileMode.Open))
        {
            form.ImportXml(xfdfInputStream);
        }
                
        // Import data XFDF
        using (var xfdfInputStream  = new FileStream(dataDir + "input.xfdf", FileMode.Open))
        {
            form.ImportXfdf(xfdfInputStream);
        }
                
        // Save PDF document
        form.Save(dataDir + "ImportDataUpdated_out.pdf");
    }
}

Export Data from FDF into a PDF File

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.Pdf-for-.NET
private static void ExportData()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdfFacades_Forms();

    using (var form = new Aspose.Pdf.Facades.Form())
    {
        // Bind PDF document
        form.BindPdf(dataDir + "input.pdf");
                
        // Create FDF file
        using (var fdfOutputStream = new FileStream(dataDir + "data_out.fdf", FileMode.Create))
        {
            form.ExportXfdf(fdfOutputStream);
        }
                
        // Create XML file
        using (var xmlOutputStream = new FileStream(dataDir + "data_out.xml", FileMode.Create))
        {
            form.ExportXfdf(xmlOutputStream);
        }
            
        // Create XFDF file
        using (var xfdfOutputStream = new FileStream(dataDir + "data_out.xfdf", FileMode.Create))
        {
            form.ExportXfdf(xfdfOutputStream);
        }              
    }
}