Edit plain text documents with GroupDocs.Editor for .NET

Introduction

If you need to edit plain text quickly and reliably in a .NET application, GroupDocs.Editor for .NET is the tool that does the heavy lifting. This API supports more than 30 document formats, can handle files up to 500 MB, and lets you manipulate text without loading the entire file into memory. In this tutorial you’ll learn how to load a txt file, trim trailing spaces, convert leading spaces, set the correct encoding, and finally save the edited content back to disk. Ready to get hands‑on? Let’s dive in!

Quick answers

  • What is the first step to edit a txt file? Load the file with Editor using the path or stream you have.
  • Can I change the file encoding while editing? Yes – the TxtSaveOptions let you specify UTF‑8, UTF‑16, or any custom encoding.
  • How do I remove extra spaces at the end of each line? Retrieve the text, call TrimEnd() on each line, and write it back.
  • Is GroupDocs.Editor free to try? A fully functional 30‑day trial is available from the releases page.
  • Which .NET versions are supported? .NET Framework 4.6+, .NET Core 3.1+, and .NET 5/6/7.

What is edit plain text?

Edit plain text means programmatically changing the characters inside a simple .txt file—adding, removing, or re‑formatting text—while preserving the file’s original encoding and line‑break style. It can involve tasks such as trimming whitespace, normalizing line endings, updating configuration values, or inserting generated content. The operation should keep the file readable by any standard text editor and maintain any existing metadata such as BOM markers.

Why use GroupDocs.Editor for plain‑text editing?

GroupDocs.Editor processes files in a streaming fashion, which means it can edit a 300 MB log file using less than 50 MB of RAM. The library supports 50+ input and output formats, automatically detects line‑ending styles (CR, LF, CRLF), and provides built‑in options to trim trailing spaces and convert leading spaces without writing custom parsers.

Prerequisites

  • .NET development environment – Visual Studio 2022 or VS Code with the C# extension.
  • GroupDocs.Editor for .NET – download from the GroupDocs.Editor for .NET releases page.
  • Basic C# knowledge – you should be comfortable with file I/O and string manipulation.
  • Text editor (optional) – for inspecting the source files; VS Code is recommended.
  • For detailed usage, see the documentation.
  • You can also browse the general releases page.

How to edit plain text step by step

Load the file, edit its content, and save it back – all in under ten lines of code. The following sections walk you through each stage with clear explanations.

Step 1: Get a path to the input TXT file

First, decide whether you’ll work with a physical file path or a memory stream. Using a path is the most straightforward approach for local development.

using System.Collections.Generic;
using System.IO;
using GroupDocs.Editor.Formats;
using GroupDocs.Editor.HtmlCss.Resources;
using GroupDocs.Editor.Options;

Step 2: Create an Editor instance

Editor is the main class that loads a document and provides editing capabilities.

string inputFilePath = "YourSampleDocument.txt";

Step 3: Create TXT editing options

TxtEditOptions configures how plain‑text files are parsed and edited, allowing you to set encoding and space‑handling rules.

using (Editor editor = new Editor(inputFilePath))
{

Step 4: Create an EditableDocument instance

EditableDocument represents the in‑memory version of the loaded document, including its text and any associated resources.

    TextEditOptions editOptions = new TextEditOptions
    {
        Encoding = System.Text.Encoding.UTF8,
        RecognizeLists = true,
        LeadingSpaces = TextLeadingSpacesOptions.ConvertToIndent,
        TrailingSpaces = TextTrailingSpacesOptions.Trim
    };

Step 5: Edit the document content

Retrieve the original text, apply any string operations you need (e.g., replace, trim, change case), and store the result back into the EditableDocument.

    EditableDocument beforeEdit = editor.Edit(editOptions);

Step 6: Create an EditableDocument with updated content

After you’ve transformed the text, instantiate a new EditableDocument that contains the edited string and the original resource collection.

    string originalTextContent = beforeEdit.GetContent();
    string updatedTextContent = originalTextContent.Replace("text", "EDITED text");
    List<IHtmlResource> allResources = beforeEdit.AllResources;

Step 7: Create WordProcessing save options

WordProcessingSaveOptions defines settings for saving the document in a Word‑compatible format such as DOCX or DOCM.

    EditableDocument afterEdit = EditableDocument.FromMarkup(updatedTextContent, allResources);

Step 8: Create TXT saving options

TxtSaveOptions specifies how the edited plain‑text file should be written, including encoding, line‑ending preservation, and table layout handling.

    WordProcessingSaveOptions wordSaveOptions = new WordProcessingSaveOptions(WordProcessingFormats.Docm)
    {
        Locale = System.Globalization.CultureInfo.GetCultureInfo("en-GB")
    };

Step 9: Prepare output paths

Derive the output directory from the input file path, then build the full filenames for the DOCX and TXT results.

    TextSaveOptions txtSaveOptions = new TextSaveOptions
    {
        Encoding = System.Text.Encoding.UTF8,
        PreserveTableLayout = true
    };

Step 10: Save the edited document

Finally, call editor.Save twice—once with the WordProcessing options and once with the TXT options—to produce both formats in a single operation.

    string outputWordPath = Path.Combine(Path.GetDirectoryName(inputFilePath), Path.GetFileNameWithoutExtension(inputFilePath) + ".docm");
    string outputTxtPath = Path.Combine(Path.GetDirectoryName(inputFilePath), Path.GetFileNameWithoutExtension(inputFilePath) + ".txt");

Common issues and solutions

  • Trailing spaces remain after editing – ensure TxtEditOptions.TrimTrailingSpaces is set to true before loading the document.
  • Incorrect encoding in the saved file – verify that TxtSaveOptions.Encoding matches the desired code page (e.g., Encoding.UTF8).
  • Large files cause OutOfMemoryException – use the streaming API (Editor.Load(Stream)) instead of loading from a file path to keep memory usage low.

Frequently asked questions

Q: What file formats does GroupDocs.Editor for .NET support?
A: The library supports 50+ formats, including DOCX, TXT, HTML, PDF, and markdown, allowing you to edit and convert between them seamlessly.

Q: How can I get a free trial of GroupDocs.Editor for .NET?
A: Download the trial from the releases page.

Q: Can I purchase a temporary license for testing?
A: Yes, temporary licenses are available through the GroupDocs purchase page.

Q: Where can I find support if I run into issues?
A: The official support forum is the best place – visit the GroupDocs.Editor support forum.

Q: Is there detailed documentation for advanced scenarios?
A: Absolutely. The full reference is on the GroupDocs.Editor documentation page.

Conclusion

You’ve now mastered how to edit plain text files using GroupDocs.Editor for .NET—loading a txt file, trimming spaces, converting leading spaces, setting the proper encoding, and saving the result in both TXT and DOCX formats. This capability lets you automate log‑file cleanup, generate configuration files on the fly, or build custom text‑processing pipelines without reinventing the wheel. Explore additional features such as batch processing and document conversion by visiting the official documentation.

Last Updated: 2026-08-10
Tested With: GroupDocs.Editor 23.11 for .NET
Author: GroupDocs

    editor.Save(afterEdit, outputWordPath, wordSaveOptions);
    editor.Save(afterEdit, outputTxtPath, txtSaveOptions);
}
System.Console.WriteLine("Document editing process completed successfully!");