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C# Dev Tools

Code Navigation & IntelliSense

Unused Symbol Detection

Identify and eliminate dead code with unused symbol highlighting.

Overview

Section titled “Overview”

Unused symbol detection automatically highlights code that isn’t being used anywhere in your project.

What Gets Detected

Section titled “What Gets Detected”

Private Methods

Section titled “Private Methods”

Private methods with no references:

private void UnusedMethod() // Appears grayed out
{
    // This method is never called
}

Properties

Section titled “Properties”

Public and private properties not accessed:

private string UnusedProperty { get; set; } // Grayed out

Fields

Section titled “Fields”

Fields that are declared but never used:

private int _unusedField; // Grayed out

Events

Section titled “Events”

Events that are never subscribed to or raised:

private event EventHandler UnusedEvent; // Grayed out

Visual Indication

Section titled “Visual Indication”

Unused symbols appear with reduced opacity (grayed out), making them easy to spot.

Configuration

Section titled “Configuration”

Enable/Disable

Section titled “Enable/Disable”
  1. Open Settings (Ctrl+,)
  2. Search for csharp-dev-tools.editor.highlightUnusedSymbols
  3. Toggle on/off

Or use Command Palette: “Toggle Unused Symbol Highlighting”

Adjust Opacity

Section titled “Adjust Opacity”

Control how grayed out unused symbols appear:

  1. Search for csharp-dev-tools.editor.unusedSymbolOpacity
  2. Set value between 0.1 (very faint) and 1.0 (normal)

Detection Method

Section titled “Detection Method”

The extension uses:

  1. Primary: C# Language Server diagnostics (IDE0051, etc.)
  2. Fallback: Reference counting for larger files
  3. Scope: File-level detection for performance

Exclusions

Section titled “Exclusions”

Public Methods

Section titled “Public Methods”

Public methods are excluded from detection as they might be:

  • API endpoints
  • Library methods
  • Called from external projects
  • Used via reflection

Interface Implementations

Section titled “Interface Implementations”

Methods implementing interfaces are excluded even if not directly called.

Virtual/Override Methods

Section titled “Virtual/Override Methods”

Virtual and override methods are excluded as they may be called via polymorphism.

Use Cases

Section titled “Use Cases”

Code Cleanup

Section titled “Code Cleanup”
  • Identify methods to remove
  • Find unused properties
  • Eliminate dead code
  • Reduce technical debt

Refactoring

Section titled “Refactoring”
  • Safely remove unused code
  • Simplify classes
  • Improve maintainability

Code Review

Section titled “Code Review”
  • Spot accidentally unused code
  • Find leftover experimental code
  • Identify incomplete refactorings

Best Practices

Section titled “Best Practices”
  • Review grayed out code before deleting
  • Check if code is intentionally unused (future use)
  • Consider making unused public methods private
  • Remove truly dead code to reduce complexity

Troubleshooting

Section titled “Troubleshooting”

False Positives

Section titled “False Positives”

If actively used code appears unused:

  • May be called via reflection
  • Used in other projects/assemblies
  • Called from markup (Blazor, XAML)
  • Toggle off the feature for those files

Not Detecting Unused Code

Section titled “Not Detecting Unused Code”
  • Ensure C# Language Server is running
  • Check file is part of project
  • Verify diagnostic level includes information
  • Rebuild project if needed

Performance

Section titled “Performance”
  • Lightweight detection
  • Incremental updates
  • Optimized for large files
  • Minimal performance impact