Getting Started Guide

How to Install and Use ILSpy

This guide covers installing ILSpy and using it to decompile .NET assemblies to readable C# source code across all platforms.

Prerequisites

-.NET Runtime (for CLI tool) or Windows (for GUI)

Official Documentation

Install ILSpy

ILSpy is available as a Windows GUI, VS Code extension, and cross-platform CLI tool.

CLI (cross-platform)

dotnet tool install ilspycmd -g

Verify

ilspycmd --version

Windows GUI

choco install ilspy

Decompile via CLI

Decompile a .NET assembly to C# source files from the command line.

Decompile to directory

ilspycmd -p -o output/ target.dll

Decompile single type

ilspycmd target.dll -t Namespace.ClassName

GUI Navigation

Open assemblies in the GUI and browse decompiled code.

GUI steps

# File > Open > Select assembly
# Browse namespaces and types in the tree
# Click any type/method to see decompiled C#
# View > IL Code to see intermediate language alongside C#

Search and Analyze

Find specific code patterns across loaded assemblies.

# Edit > Search (F3)
# Search types, members, or constants
# Analyze window (Ctrl+R) shows 'Used By' and 'Uses' for any member

Note: ILSpy focuses on decompilation quality. If you need debugging, use dnSpy instead. If you need cross-platform CLI decompilation, ILSpy is the better choice.

Back to ILSpy Full Documentation