Understanding .editorconfig: The Ultimate Guide for .NET Developers

What is .editorconfig?

.editorconfig is a file format that defines coding styles and standards across different editors and IDEs. It ensures consistent code formatting across your entire development team, regardless of their chosen development environment.

Key Benefits

• Consistent code style across projects
• IDE-agnostic configuration
• Enforced standards through compiler warnings/errors
• Reduced code review friction
• Automated formatting on save

Core Concepts

File Structure

The .editorconfig file uses a simple INI-style format with sections for different file types:

[*]           # All files
[*.cs]        # C# specific
[*.{xaml,xml} # Multiple file types

Basic Settings

Essential configurations include:

• indent_style (tabs vs spaces)
• indent_size
• charset
• end_of_line
• insert_final_newline
• trim_trailing_whitespace

Naming Conventions

.NET projects benefit from strict naming rules:

# Interface naming
dotnet_naming_rule.interface_should_be_begins_with_i.severity = error
dotnet_naming_rule.interface_should_be_begins_with_i.symbols = interface
dotnet_naming_rule.interface_should_be_begins_with_i.style = begins_with_i

# Private fields
dotnet_naming_rule.private_fields_should_be_camel_case.severity = warning
dotnet_naming_rule.private_fields_should_be_camel_case.symbols = private_fields
dotnet_naming_rule.private_fields_should_be_camel_case.style = camel_case_underscore_style

Real-World Examples from Production Code

MAUI Project Configuration

From a production MAUI project:

# Editor configuration, see http://editorconfig.org
root = true

[*]
charset = utf-8
indent_style = space
indent_size = 2
insert_final_newline = true
trim_trailing_whitespace = true

[*.md]
max_line_length = off
trim_trailing_whitespace = false

Enterprise .NET Backend

From a production backend service:

[*]
charset = utf-8
indent_style = tab
indent_size = 4
insert_final_newline = true
trim_trailing_whitespace = true

[*.cs]
# IDE0047: Remove unnecessary parentheses
dotnet_diagnostic.IDE0047.severity = silent

Blazor Frontend

From a production Blazor project:

[*.{razor,cshtml}]
charset = utf-8
indent_style = space
indent_size = 4
insert_final_newline = true
trim_trailing_whitespace = true

# Component-specific rules
[*.razor]
dotnet_style_coalesce_expression = true:warning
csharp_style_expression_bodied_properties = true:warning
csharp_style_expression_bodied_methods = when_on_single_line:suggestion

Project-Specific Customization

Different project types benefit from tailored rules:

MAUI Specific

public class LoginPageModel : BaseViewModel, ISingletonDependency
{
      private readonly FilterPanelViewModel _filterPanelViewModel;
      [ObservableProperty] private DataGridViewModel _dataGridViewModel;
      [ObservableProperty] private bool _filterPanelVisible;
}

Demonstrates proper naming conventions and attribute usage in MAUI.

API Controllers

public class WeatherForecastController : ControllerBase
{
      private readonly ILogger<WeatherForecastController> _logger;
    
      public async Task<IActionResult> GetForecast()
      {
          // Implementation
      }
}

Shows API-specific formatting and dependency injection patterns.

Advanced Features

Severity Levels

• error: Must be fixed to compile
• warning: Should be fixed
• suggestion: Consider fixing
• silent: Documentation only

File-Specific Rules

Different file types need different rules:

# C# files
[*.cs]
indent_size = 4

# Project files
[*.{csproj,vbproj}]
indent_size = 2

IDE Integration

Rider Code Cleanup Options

1. Full Cleanup
   • Complete code standardization
   • Applies all formatting rules
   • Perfect for new projects
2. Reformat Code
   • Quick visual formatting
   • Ideal for quick fixes
   • Safe for small changes
3. Reformat & Apply Syntax Style
   • Balanced approach
   • Updates code patterns
   • Good for regular maintenance

Best Practices

1. Start with a comprehensive template
2. Customize based on team preferences
3. Document any deviations from standards
4. Regular code cleanup passes
5. Include .editorconfig in source control

Team Workflow Integration

1. Configure IDE settings
2. Run cleanup before commits
3. Validate in CI/CD pipeline
4. Review formatting in PRs
5. Regular team standard reviews

Conclusion

.editorconfig is essential for maintaining code quality and consistency. The real-world examples demonstrate its effectiveness across different project types and team sizes. Start with these templates, customize to your needs, and let the tools work for you!

This comprehensive guide, backed by production code examples and practical workflows, provides everything needed to implement effective code styling in your .NET projects.