# Extension Method: Flatten Forms Fields in PDF Documents using .NET C# > This article shows how to flatten form fields in TX Text Control before exporting the document to PDF. This is a common requirement when documents should be shared with others and the form fields should not be changed anymore. - **Author:** Bjoern Meyer - **Published:** 2024-07-17 - **Modified:** 2025-11-16 - **Description:** This article shows how to flatten form fields in TX Text Control before exporting the document to PDF. This is a common requirement when documents should be shared with others and the form fields should not be changed anymore. - **3 min read** (427 words) - **Tags:** - ASP.NET - ASP.NET Core - PDF - Form Fields - **Web URL:** https://www.textcontrol.com/blog/2024/07/17/flatten-forms-fields-in-pdf-documents-using-net-c-sharp/ - **LLMs URL:** https://www.textcontrol.com/blog/2024/07/17/flatten-forms-fields-in-pdf-documents-using-net-c-sharp/llms.txt - **LLMs-Full URL:** https://www.textcontrol.com/blog/2024/07/17/flatten-forms-fields-in-pdf-documents-using-net-c-sharp/llms-full.txt --- TX Text Control provides extensive functionality for creating form documents with form fields such as text boxes, checkboxes, or drop-down lists. These documents can be deployed using TX Text Control UI components that help users fill out these forms, or you can programmatically create fillable PDFs. When a document is completed and you want to export and share the completed document as a PDF, form fields are typically flattened. This means that the form fields are converted to static text and the user can't change the content of the form fields anymore. ### Flatten Form Fields TX Text Control provides an overload of the FormFieldCollection.Remove method that does not delete the content and replaces it with plain text. In order to make it very easy to use, in this article we have implemented two extension methods for the *FormFieldCollection*. ``` using TXTextControl; public static class FormFieldExtender { public static void Flatten(this FormFieldCollection formFields, FormField formField) { formFields.Remove(formField, true); } public static void Flatten(this FormFieldCollection formFields) { int fieldCount = formFields.Count; for (int i = 0; i < fieldCount; i++) { TextFieldCollectionBase.TextFieldEnumerator fieldEnum = formFields.GetEnumerator(); fieldEnum.MoveNext(); FormField curField = (FormField)fieldEnum.Current; formFields.Remove(curField, true); } } } ``` The first implementation removes a specific form field from the collection and replaces it with plain text. The second implementation removes all form fields from the collection and replaces them with plain text. These extension methods can be used in the following way: ``` FormField curField = textControl1.FormFields.GetItem(3); textControl1.FormFields.Flatten(curField); ``` The above code snippet removes one specific form field from the collection and replaces it with plain text. When you want to remove all form fields from the collection and replace them with plain text, you can use the following code snippet: ``` textControl1.FormFields.Flatten(); ``` Typically, you would flatten the form fields before exporting the document to PDF. The following code snippet shows how to flatten all form fields in a document and to export the document to PDF: ``` using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl()) { tx.Create(); // Load a document with form fields tx.Load("form1.tx", StreamType.InternalUnicodeFormat); // Flatten all form fields tx.FormFields.Flatten(); // Save the document as PDF tx.Save("form1.pdf", StreamType.AdobePDF); } ``` ### Conclusion Flattening form fields in a document is a common requirement when exporting documents to PDF. The extension methods provided in this article help to flatten form fields in a document and replace them with plain text. These methods can be used to remove specific form fields or all form fields from a document. The flattened document can be exported to PDF and shared with others. --- ## About Bjoern Meyer As CEO, Bjoern is the visionary behind our strategic direction and business development, bridging the gap between our customers and engineering teams. His deep passion for coding and web technologies drives the creation of innovative products. If you're at a tech conference, be sure to stop by our booth - you'll most likely meet Bjoern in person. With an advanced graduate degree (Dipl. Inf.) in Computer Science, specializing in AI, from the University of Bremen, Bjoern brings significant expertise to his role. In his spare time, Bjoern enjoys running, paragliding, mountain biking, and playing the piano. - [LinkedIn](https://www.linkedin.com/in/bjoernmeyer/) - [X](https://x.com/txbjoern) - [GitHub](https://github.com/bjoerntx) --- ## Related Posts - [Create Fillable PDF Forms in .NET C#](https://www.textcontrol.com/blog/2024/11/12/create-fillable-pdf-forms-in-net-c-sharp/llms.txt) - [Using QR Codes in PDF Documents in C# .NET](https://www.textcontrol.com/blog/2026/04/21/using-qr-codes-in-pdf-documents-in-csharp-dotnet/llms.txt) - [Why Structured E-Invoices Still Need Tamper Protection using C# and .NET](https://www.textcontrol.com/blog/2026/03/24/why-structured-e-invoices-still-need-tamper-protection-using-csharp-and-dotnet/llms.txt) - [Create Fillable PDFs from HTML Forms in C# ASP.NET Core Using a WYSIWYG Template](https://www.textcontrol.com/blog/2026/03/17/create-fillable-pdfs-from-html-forms-in-csharp-aspnet-core-using-a-wysiwyg-template/llms.txt) - [Why HTML to PDF Conversion is Often the Wrong Choice for Business Documents in C# .NET](https://www.textcontrol.com/blog/2026/03/13/why-html-to-pdf-conversion-is-often-the-wrong-choice-for-business-documents-in-csharp-dot-net/llms.txt) - 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