Field appearance and attributes

FormEditor class of Aspose.Pdf.Facades namespace allows you to not only change the look and feel of the form field, but also the behavior of the field. In this article, we will see how we can use FormEditor class to change the field appearance, field attributes, and the field limit as well.

Implementation details

SetFieldAppearance method is used to the change the appearance of a form field. It takes AnnotationFlag as a parameter. AnnotationFlag is an enumeration which has different members like Hidden or NoRotate etc.

SetFieldAttributes method is used to change the attribute of a form field. A parameter passed to this method is PropertyFlag enumeration which contains members like ReadOnly or Required etc.

FormEditor class also provides a method to set the field limit. It tells the field that how much characters it can be filled with. The bellow code snippet shows you how all of these methods can be used.

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

     // Open PDF document
     using (var doc = new Aspose.Pdf.Document(dataDir + "FilledForm.pdf"))
     {
         // Create an instance of FormEditor to manipulate form fields
         using (var formEditor = new Aspose.Pdf.Facades.FormEditor(doc))
         {
             // Add a new text field to the form on page 1 at the specified coordinates and size
             formEditor.AddField(Aspose.Pdf.Facades.FieldType.Text, "text1", 1, 200, 550, 300, 575);

             // Set the field attribute to make the text field required (user must fill it)
             formEditor.SetFieldAttribute("text1", Aspose.Pdf.Facades.PropertyFlag.Required);

             // Set a character limit for the field (maximum 20 characters)
             formEditor.SetFieldLimit("text1", 20);

             // Save PDF document
             formEditor.Save(dataDir + "ChangingFieldAppearance_out.pdf");
         }
     }
 }