Opinionated.DotNet.CodingStandards 0.0.15

Opinionated.DotNet.CodingStandards

Strongly opinionated coding standards for .NET — a single development-dependency package that wires in five Roslyn analyzer packages plus a curated editorconfig, MSBuild props, and targets so every project in your solution enforces the same quality bar automatically.

Installation

Recommended: centralise across the whole solution

The point of this package is that every project in a solution enforces the same standards. The cleanest way to guarantee that is Central Package Management (CPM) with a GlobalPackageReference. Declaring it once in a Directory.Packages.props at the solution root applies it to every project automatically — no per-project edits, and no risk of one project drifting out of line.

Create (or edit) Directory.Packages.props next to your .slnx:

<Project>
  <PropertyGroup>
    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
  </PropertyGroup>

  <ItemGroup>
    
    <GlobalPackageReference Include="Opinionated.DotNet.CodingStandards" Version="0.0.2" />
  </ItemGroup>
</Project>

A GlobalPackageReference is implicitly a development-only dependency (PrivateAssets="all"), so it never flows to your published assemblies or transitive consumers, and you never repeat the reference in individual .csproj files.

Single project

For a one-off project, add it directly instead:

dotnet add package Opinionated.DotNet.CodingStandards

Because it is a developmentDependency package it has no impact on your published assemblies or transitive consumers.

Rule reference

The full table of enforced rules (rule ID, description, severity, help link) is in docs/rule-reference.md in the repository.

Configurable ban toggles

Seven banned-API groups are enabled by default. Each can be opted out of individually by setting the corresponding MSBuild property to false in your project file or in a Directory.Build.props.

<PropertyGroup>
  
  <BanNonUtcDateApis>false</BanNonUtcDateApis>
  <BanInvariantCultureStringComparisonApis>false</BanInvariantCultureStringComparisonApis>
  <BanEnumTryParseWithoutIgnoreCaseApis>false</BanEnumTryParseWithoutIgnoreCaseApis>
  <BanRoundWithoutMidpointRoundingApis>false</BanRoundWithoutMidpointRoundingApis>
  <BanUseOfCultureInfoConstructorApis>false</BanUseOfCultureInfoConstructorApis>
  <BanUseOfTupleInFavourOfValueTupleApis>false</BanUseOfTupleInFavourOfValueTupleApis>
  <BanUseOfNewtonsoftJsonApis>false</BanUseOfNewtonsoftJsonApis>
</PropertyGroup>

Style and naming conventions

The following choices are configured via editorconfig and apply across the solution. They are enforced as IDE suggestions where a Roslyn diagnostic exists; otherwise they are expressed as editorconfig formatting rules.

var usage

Use var everywhere the type is apparent or inferred — for built-in types, when the type appears on the right-hand side, and everywhere else.

var count = 0;
var items = new List<string>();
var result = GetResult();

Namespace declarations

File-scoped namespaces (namespace Foo;) are preferred over block-scoped (namespace Foo { … }).

Braces

All control-flow blocks (if, for, while, etc.) must use braces, even for single-line bodies.

Expression-bodied members

• Properties and accessors: expression bodies (=>) preferred.
• Methods and constructors: block bodies preferred.

Operator placement when wrapping

When a binary expression wraps across lines, the operator goes at the beginning of the continuation line.

Accessibility modifiers

Explicit accessibility modifiers are required on all non-interface members.

Naming conventions

using directives

• Placed outside the namespace declaration.
• System.* directives sorted first.
• No blank lines between import groups.

Language keywords vs BCL types

Use language keywords (int, string, bool) rather than BCL type names (Int32, String, Boolean) for both locals and member access.

Nullable reference types and warnings-as-errors

Nullable context is enabled and all warnings are treated as errors. implicit usings and the latest C# language version are also set by default.