SimpleIDE

A lightweight, professional VB.NET IDE built with GTK# 3 on Linux using .NET 8.0. SimpleIDE provides a modern development environment specifically designed for VB.NET projects on Linux systems.

Discord Channel

https://discordapp.com/channels/682603493386747904/1408457691734737007

Features

Code Editor

• Multi-file tabbed editing with automatic file type detection
• VB.NET syntax highlighting with customizable color themes
• Line numbers with click-to-select and drag-to-select functionality
• Smart indentation and automatic bracket matching
• Undo/Redo system (Ctrl+Z, Ctrl+R) with per-character tracking
• Code folding for classes, methods, properties (including Get/Set), and regions
• Intelligent code completion with hover tooltips and parameter hints

Syntax errors (as opposed to highlighting) are not flagged inline in the editor - there's no squiggly-underline diagnostics pass yet; error/warning navigation happens through the build output panel instead (see Build System below).

Project Management

• Project Explorer with .vbproj file parsing and management
• Object Explorer showing hierarchical code structure
• Auto-detection of project files in current directory
• Solution and project file support (.sln, .vbproj)
• Reference management for NuGet packages and assemblies

Build System

• Integrated build system using dotnet CLI
• Async build operations with real-time output
• Build output panel (in the toggleable bottom panel) with error/warning navigation
• One-click build and run (F5/F6)
• Support for Debug and Release configurations
• Click-to-navigate error and warning messages

AI Integration

• Choice of AI backend: Anthropic's Claude API, the locally-installed Claude Code CLI (uses its own login, no API key needed), OpenRouter, or any local LLM server speaking the OpenAI-compatible chat completions API (Ollama, LM Studio, etc.) - configured in Preferences > AI
• Claude AI assistant panel for code generation, refactoring, explaining code, and generating documentation, with a per-message prompt built from the current file's content
• Artifact extraction - code/doc blocks in the AI's response are parsed out and can be applied to a file or opened in a diff view
• Streaming responses and persistent conversation history (restored across restarts, capped via a configurable limit in Preferences) - one continuous, disk-persisted conversation, not scoped per-project and without a multi-conversation browser yet
• API keys are stored via the OS keyring (or an encrypted-file fallback), never in plain settings

User Interface

• Several built-in color themes (Default Dark, Monokai, Solarized Dark/Light, Dracula, GitHub Dark, One Dark, and more), plus a System Colors theme that follows the desktop/GTK theme's actual background, text, and accent colors (re-sampled each time it's selected, not just once at startup) - all switched manually from the Themes menu or Preferences
• Customizable toolbar with common actions
• Enhanced status bar showing cursor position, language mode, and encoding
• Welcome splash screen with recent projects
• Toggleable bottom panel (Build Output, Git, TODO List, Console, AI Assistant tabs) - show/hide as a whole, not independently floatable/rearrangeable
• Integrated help system with searchable documentation (search delegates to a learn.microsoft.com search rendered in the embedded browser, not a local index)

Developer Tools

• Git integration for version control operations (stage/commit/push/pull/branch, from the Git panel or menu)
• Find and Replace with regex support - Find is Ctrl+F, Replace is Ctrl+H (see Keyboard Shortcuts below)
• Go to line navigation (Ctrl+G)
• Block commenting (Ctrl+/)
• Settings persistence across sessions

Installation

Prerequisites

• Linux operating system (Ubuntu 20.04+, Debian 11+, Fedora 34+, or similar)
• .NET 8.0 SDK
• GTK# 3.24 or higher
• Git

Install .NET 8.0

# Ubuntu/Debian
wget https://packages.microsoft.com/config/debian/12/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
rm packages-microsoft-prod.deb
sudo apt-get update
sudo apt-get install -y dotnet-sdk-8.0

# Fedora
sudo dnf install dotnet-sdk-8.0

Install GTK# Dependencies

# Ubuntu/Debian
sudo apt-get install libgtk-3-0 libgtk-3-dev

# Fedora
sudo dnf install gtk3 gtk3-devel

Build SimpleIDE

SimpleIDE is split across three sibling repos, referenced via relative ProjectReferences - clone all three into the same parent directory:

# Clone all three repos as siblings
git clone https://github.com/jamesplotts/simpleide.git
git clone https://github.com/jamesplotts/SimpleIDE.Widgets.git
git clone https://github.com/jamesplotts/SimpleIDE.WebKitGtk.git
cd simpleide

# Restore dependencies
dotnet restore SimpleIDE.sln

# Build the project
dotnet build SimpleIDE.sln --configuration Release

# Run SimpleIDE
dotnet run --project SimpleIDE.vbproj --configuration Release

SimpleIDE.vbproj is the main app; SimpleIDE.Widgets is the reusable control library; SimpleIDE.WebKitGtk is the WebKitGTK rendering backend (see "Embedded browser architecture" below) - all three referenced from SimpleIDE.sln. With more than one project file present, dotnet commands need to be told explicitly which one to use - hence SimpleIDE.sln for build/restore and --project SimpleIDE.vbproj for run/publish, rather than the bare dotnet build/dotnet run that worked with the old single-project layout.

Embedded browser architecture (Help tab)

The Help tab renders real documentation pages (e.g. learn.microsoft.com) inline through one of two interchangeable rendering backends, selected automatically at runtime by Managers/EmbeddedBrowserFactory.vb:

1. WebKitGTK (SimpleIDE.WebKitGtk.vbproj, Widgets/CustomDrawWebView.vb) - full, real, JavaScript-capable rendering via the system's libwebkit2gtk-4.1. Preferred whenever that library is present. Linux-only (WebKitGTK has no Windows build), hand-rolled P/Invoke against the native C API rather than any pre-built binding (see Interop/WebKitNative.vb's header comment for why).
2. litehtml (Widgets/CustomDrawHtmlView.vb, vendored native shim) - lightweight, genuinely cross-platform, but no JavaScript at all. Always available once its bundled .so is built (see below), and the automatic fallback whenever WebKitGTK isn't - which also makes it the only backend on a platform that doesn't have WebKitGTK.

Both are entirely optional in the sense that the Help tab still works with neither built: SimpleIDE just opens links in your system's default browser instead, exactly as before either backend existed. A Preferences toggle ("Prefer native WebKit rendering when available", General tab) lets you force the litehtml fallback for troubleshooting without uninstalling WebKitGTK.

Building the litehtml backend

The litehtml source (a submodule) and native shim build live in the SimpleIDE.Widgets repo, not here:

# Ubuntu/Debian
sudo apt-get install -y cmake pkg-config libcairo2-dev libpango1.0-dev libgdk-pixbuf-2.0-dev

# Fedora
sudo dnf install cmake pkgconf-pkg-config cairo-devel pango-devel gdk-pixbuf2-devel

# From the SimpleIDE.Widgets checkout (sibling of this repo):
cd ../SimpleIDE.Widgets

# Fetch the vendored litehtml source (submodule)
git submodule update --init --recursive

# Build the native shim
./native/build-native.sh

This produces SimpleIDE.Widgets/native/build/lib/liblitehtml_shim.so; a subsequent dotnet build of SimpleIDE.sln (from this repo) picks it up automatically via the SimpleIDE.Widgets ProjectReference and bundles it into SimpleIDE's own output directory. No native toolchain is required to build or run SimpleIDE itself - this step is purely additive.

Building the WebKitGTK backend

Nothing to build - SimpleIDE.WebKitGtk.vbproj is pure managed code (P/Invoke, no vendored native source). It just needs libwebkit2gtk-4.1-0 installed at runtime:

# Ubuntu/Debian
sudo apt-get install -y libwebkit2gtk-4.1-0

# Fedora
sudo dnf install webkit2gtk4.1

CustomDrawWebView.IsAvailable probes for this at runtime (never a hard DllNotFoundException) and the factory falls back to litehtml if it's missing.

Porting to another platform (e.g. Windows)

This is the reason Widgets/ was split into its own assembly (and, later, its own repo) in the first place. A fork targeting Windows (or any platform without WebKitGTK) doesn't need to touch or understand the rest of the app:

1. Clone SimpleIDE.Widgets as a sibling and reference it (the reusable control library - buttons, text boxes, CustomDrawHtmlView, theming, etc. - none of it Linux-specific).
2. Implement Interfaces/IEmbeddedBrowserView (defined in SimpleIDE.Widgets) against whatever rendering engine is available on the target platform - WebView2 and CEF are the natural choices on Windows - as a Gtk.Widget subclass in a new SimpleIDE.<Backend> repo/project, following SimpleIDE.WebKitGtk's Widgets/CustomDrawWebView.vb as a reference implementation (its P/Invoke specifics are WebKitGTK-only, but the widget-lifecycle pattern - wrap a native view as a child widget, forward navigation events, no navigation policy of its own - carries over).
3. Add one more preference check to Managers/EmbeddedBrowserFactory.Create().

Nothing in HelpBrowser.vb or anywhere else in the main app needs to change - it only ever talks to the IEmbeddedBrowserView interface, never a concrete provider type.

Usage

Command Line Interface

# Launch with auto-detection (finds .vbproj in current directory)
SimpleIDE

# Open specific project
SimpleIDE MyProject.vbproj

# Create new project
SimpleIDE -n MyApp -t Console

# Show help (lists all available options)
SimpleIDE --help

# Show version information
SimpleIDE --version

Run SimpleIDE --help for the full list of options - there are quite a few beyond the basics above (window state, safe mode, settings reset, and several project-maintenance flags).

Test Mode for Diagnostics (For Claude/AI Assistants)

IMPORTANT FOR CLAUDE: The IDE has a special test mode that allows running it headlessly with automatic exit for diagnostic purposes. This is particularly useful when debugging parsing issues or checking project loading without a display.

# Run in test mode - exits after 5 seconds by default
dotnet run --project SimpleIDE.vbproj -- --test-mode

# Run with custom delay (in milliseconds)
dotnet run --project SimpleIDE.vbproj -- --test-delay 5000 --test-mode

# Test with a specific project
dotnet run --project SimpleIDE.vbproj -- --test-mode --project /path/to/project.vbproj

# Build and test
dotnet build SimpleIDE.sln
dotnet run --project SimpleIDE.vbproj -- --test-mode --test-delay 3000

(--project SimpleIDE.vbproj is required now that the repo root has multiple project files - see "Build SimpleIDE" above. A bare dotnet run/dotnet build errors with MSB1011: Specify which project or solution file to use.)

If you're running without a real X11/Wayland display available (e.g. a bare CI container), wrap the command with xvfb-run -a. A real display is used directly otherwise - xvfb is not a hard requirement.

What Test Mode Does:

• Starts the IDE and automatically loads the project (auto-detects or uses --project)
• Outputs all parsing and loading diagnostics to console
• Shows which files are being parsed and any errors
• Exits automatically after the specified delay
• Useful for checking if Object Explorer population is working
• Helps diagnose Roslyn parser initialization issues

Keyboard Shortcuts

File Operations

• Ctrl+S - Save current file
• Ctrl+Shift+S - Save all files

Editing

• Ctrl+Z - Undo
• Ctrl+Shift+Z / Ctrl+R - Redo
• Ctrl+Y - Cut current line (VB.NET classic shortcut)
• Ctrl+X - Cut
• Ctrl+C - Copy
• Ctrl+V - Paste
• Ctrl+Shift+V - Smart paste (strips comment markers and re-indents to the paste location)
• Ctrl+A - Select all
• Ctrl+F - Find
• Ctrl+H - Find and replace
• Ctrl+G - Go to line
• Ctrl+/ - Toggle line comment
• Tab / Shift+Tab - Indent / outdent the current selection
• Ctrl+Space - Trigger code completion (CodeSense) at the cursor

View

• Ctrl++ / Ctrl+- / Ctrl+0 - Zoom in / out / reset editor font size
• Ctrl+E - Toggle Project Explorer
• F11 - Toggle full screen

Build and Run

• F5 - Build and run
• F6 - Build project
• Ctrl+B - Build project

Navigation

• F1 - Context-sensitive help
• F2 - Quick find from clipboard
• F3 / Shift+F3 - Find next / previous
• F12 - Go to definition
• Ctrl+Tab - Next tab
• Escape - Context-sensitive close (code completion popup, then Find panel, then clears selection)

Some shortcuts shown in menus (Find in Files, Build Solution, Run without debugging) are wired up but not yet implemented behind the scenes.

Project Structure

SimpleIDE/
├── Program.vb                        # Entry point
├── MainWindow.vb                     # Main IDE window
├── MainWindow.*.vb                   # Partial classes for main window
├── Editors/
│   ├── CustomDrawingEditor.vb        # Main code editor implementation
│   └── CustomDrawingEditor.*.vb      # Partial classes (folding, drawing, keyboard, etc.)
├── Widgets/
│   ├── CustomDrawProjectExplorer.vb  # Project tree view
│   ├── CustomDrawObjectExplorer.vb   # Code structure view
│   └── BuildOutputPanel.vb           # Build output display
├── Models/
│   └── SourceFileInfo.vb             # File content and metadata
├── Syntax/
│   ├── SyntaxNode.vb                 # Syntax tree node representation
│   └── VBSyntaxHighlighter.vb        # Syntax highlighting engine
├── Parsers/
│   └── RoslynConverter.vb            # Converts Roslyn syntax trees to SimpleIDE's model
├── Managers/
│   ├── ProjectManager.vb             # Project file management
│   └── BuildManager.vb               # Build system integration
├── Utilities/
│   └── FileOperations.vb             # File operations
└── Resources/
    └── *.png                         # Embedded icons and images

Parsing is Roslyn-based (Microsoft.CodeAnalysis.VisualBasic) rather than a hand-written parser.

This tree shows this repo's own files only. The generic, toolkit-agnostic CustomDraw* controls plus ThemeManager/SettingsManager/EditorTheme/CssHelper and CustomDrawHtmlView (with its litehtml interop) physically live in the separate SimpleIDE.Widgets repo, referenced via ProjectReference - see "Build SimpleIDE" and "Embedded browser architecture" above. Files still in this repo's Widgets//Managers//Models//Utilities/ folders are the ones with real IDE-domain coupling (Project Explorer, Object Explorer, Git panel, etc.) that don't belong in the reusable library.

Screenshots

Main Editor View

Configuration

Settings File Location

Settings are stored in ~/.config/SimpleIDE/settings.json. Code-folding expansion state is stored separately in ~/.config/SimpleIDE/foldstate.json.

Settings are managed through the IDE's Settings dialog rather than hand-edited; the file holds properties such as EditorFont, TabWidth, UseTabs, CurrentTheme, ShowLineNumbers, and SyntaxHighlighting.

Development

Coding Conventions

The project follows strict coding conventions:

1. Hungarian Notation for variables:

   • l = Local variable
   • p = Private field
   • v = Parameter
   • g = Global variable

2. Enum Pattern: All enums start with eUnspecified and end with eLastValue

3. XML Documentation: All public members must have XML documentation comments

4. Error Handling: Try-Catch blocks in all methods with console logging

Building from Source

# Debug build
dotnet build SimpleIDE.sln --configuration Debug

# Release build
dotnet build SimpleIDE.sln --configuration Release

# Create self-contained executable
dotnet publish SimpleIDE.vbproj -c Release -r linux-x64 --self-contained

Contributing

Contributions are welcome! Please follow these guidelines:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Follow the coding conventions documented in the project
4. Ensure all XML documentation is complete
5. Test your changes thoroughly
6. Commit your changes (git commit -m 'Add amazing feature')
7. Push to the branch (git push origin feature/amazing-feature)
8. Open a Pull Request

Known Issues

• TextBuffer operations require SelectRange + DeleteSelection instead of Delete
• Icon resources must use full namespace: SimpleIDE.icon.png
• GTK# Path conflicts require fully qualified System.IO.Path

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• GTK# team for the excellent .NET bindings
• Microsoft for .NET 8.0 and VB.NET
• The open source community for inspiration and support

Note: IntelliSense is a registered trademark of Microsoft Corporation. SimpleIDE's code completion features are independently developed.

Contact

• Author: James Duane Plotts
• Repository: https://github.com/jamesplotts/simpleide
• Issues: https://github.com/jamesplotts/simpleide/issues
• Donate: https://buymeacoffee.com/jamesplotts

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SimpleIDE - Bringing professional VB.NET development to Linux