# C# Naming Standards · CS-05 ## Standard Metadata - Area: C# - Owner: Backend Steering group - Last reviewed: 2026-09-09 - Next review due from: 2026-12-01 - Enforcement: CodeAnalysis / Rosyln Analyser / code review - Status: Active ## Use descriptive names · CS-05.1 · **MUST** All type members, parameters and variables should be named using words from the English language. * Choose easily readable, preferably grammatically correct names. For example, `HorizontalAlignment` is more readable than `AlignmentHorizontal`. * Favour readability over brevity. The property name `CanScrollHorizontally` is better than `ScrollableX` (an obscure reference to the X-axis). * Avoid using names that conflict with keywords of widely used programming languages. * Avoid using abbreviations. For example, the variable name `vatPercent` is better than `vatPcnt`. **EXCEPTION**: In most projects, you will use words and phrases from your domain and names specific to your company. Visual Studio's static code analysis will perform a spelling check on all code, so you may need to [customize the Spell Checker](https://learn.microsoft.com/en-us/visualstudio/ide/text-spell-checker?view=vs-2022#how-to-customize-the-spell-checker). **Roslyn Analyzer Rule [ACL1004](https://github.com/audaciaconsulting/Audacia.CodeAnalysis/blob/master/dotnet-roslyn/analyzers/Audacia.CodeAnalysis.Analyzers/README.md#acl1004---dont-use-abbreviations) (partial)** --- ## Use proper casing for language elements · CS-05.2 · **MUST** | Language element | Casing | Example | Roslyn Analyzer Rule | | ---------------------- | ---------------- | --------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Class, Struct | Pascal | `AppDomain` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Interface | Pascal | `IBusinessService` | [SA1302](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1302.md) | | Enumeration type | Pascal | `ErrorLevel` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Enumeration values | Pascal | `FatalError` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Event | Pascal | `Click` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Private field | Camel (prefixed) | `_listItem` | [ACL1000](https://github.com/audaciaconsulting/Audacia.CodeAnalysis/blob/master/dotnet-roslyn/analyzers/Audacia.CodeAnalysis.Analyzers/README.md#acl1000---private-fields-should-be-prefixed-with-an-underscore), [SA1306](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1306.md) | | Protected field | Pascal | `MainPanel` | | Const field | Pascal | `MaximumItems` | [SA1303](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1303.md) | | Const variable | Camel | `maximumItems` | | Read-only static field | Pascal | `RedValue` | [SA1311](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1311.md) | | Variable | Camel | `listOfValues` | [SA1312](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1312.md) | | Method | Pascal | `ToString` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Namespace | Pascal | `System.Drawing` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Parameter | Camel | `typeName` | [SA1313](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1313.md) | | Type Parameter | Pascal | `TView` | [SA1314](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1314.md) | | Property | Pascal | `BackColor` | [SA1300](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1300.md) | | Value Tuple | Pascal | `(int Number, string Name)` | [SA1316](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1316.md) | **NOTE**: If the name of the variable includes an acronym, the acronym should follow normal casing rules for the variable type as detailed above. For example: * A variable for a HTTP Client should be cased as `httpClient`. * A property for a HTTP Client should be cased as `HttpClient`. --- ## Don't include numbers in variables, parameters and type members · CS-05.3 · **MUST** In most cases they are a lazy excuse for not defining a clear and intention-revealing name. **Roslyn Analyzer Rule [AV1704](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1704-dont-include-numbers-in-variables-parameters-and-type-members-)** --- ## Don't prefix fields · CS-05.4 · **MUST** For example, don't use `s_` or `m_` to distinguish static versus non-static fields. **EXCEPTION**: You should prefix private instance fields with `_`, e.g. `_currentUser`. **Roslyn Analyzer Rule [SA1308](https://github.com/DotNetAnalyzers/StyleCopAnalyzers/blob/master/documentation/SA1308.md).** --- ## Name types using nouns, noun phrases or adjective phrases · CS-05.5 · **SHOULD** Bad examples include `SearchExamination` (a page for searching for examinations), `Common` (does not end with a noun, and does not explain its purpose) and `SiteSecurity` (although the name is technically okay, it does not say anything about its purpose). Good examples include `BusinessBinder`, `SmartTextBox`, or `EditableSingleCustomer`. Don't include terms like `Utility` or `Helper` in classes. Classes with a name like that are usually static classes and are introduced without considering the object-oriented principles. **Roslyn Analyzer Rule [AV1708](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1708-name-types-using-nouns-noun-phrases-or-adjective-phrases-) (partial)** --- ## Don't repeat the name of a class or enumeration in its members · CS-05.6 · **MUST** ```csharp class Employee { // Wrong! static GetEmployee() {} DeleteEmployee() {} // Right static Get() {...} Delete() {...} // Also correct. AddNewJob() {...} RegisterForMeeting() {...} } ``` **Roslyn Analyzer Rule [AV1710](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1710-dont-repeat-the-name-of-a-class-or-enumeration-in-its-members-)** --- ## Name members similarly to members of related .NET Framework classes · CS-05.7 · **MUST** .NET developers are already accustomed to the naming patterns the framework uses, so following this same pattern helps them find their way in your classes as well. For instance, if you define a class that behaves like a collection, provide members like `Add`, `Remove` and `Count` instead of `AddItem`, `Delete` or `NumberOfItems`. **Roslyn Analyzer Rule [AV1711](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1711-name-members-similarly-to-members-of-related-net-framework-classes-) (partial)** --- ## Consistently name boolean members · CS-05.8 · **SHOULD** Name Boolean members (properties, methods, etc.) consistently - so either always prefer affirmative, e.g. `CanSeek`, or always prefer negative, e.g. `CannotSeek`. --- ## Properly name properties · CS-05.9 · **SHOULD** * Do name properties with nouns, noun phrases, or occasionally adjective phrases. * Consider prefixing Boolean properties with `Is`, `Has`, `Can`, `Allows`, or `Supports`. * Consider giving a property the same name as its type. When you have a property that is strongly typed to an enumeration, the name of the property can be the same as the name of the enumeration. For example, if you have an enumeration named `CacheLevel`, a property that returns one of its values can also be named `CacheLevel`. **Roslyn Analyzer Rule [AV1715](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1715-properly-name-properties-)** --- ## Name methods using verb-object pair · CS-05.10 · **SHOULD** Name methods using a verb-object pair such as `ShowDialog`. A good name should give the member a hint on the *what*, and if possible, the *why*. Also, don't include `And` in the name of the method. It implies that the method is doing more than one thing, which violates the single responsibility principle explained in [here](/standards/engineering/coding-standards/csharp/cs-member-design#a-method-or-property-does-only-one-thing). --- ## Name namespaces using names, layers, verbs and features · CS-05.11 · **MUST** For instance, the following namespaces are good examples of that guideline. * `NHibernate.Extensibility` * `Microsoft.ServiceModel.WebApi` * `Microsoft.VisualStudio.Debugging` * `FluentAssertion.Primitives` * `CaliburnMicro.Extensions` **NOTE**: Never allow namespaces to contain the name of a type, but a noun in its plural form, e.g. `Collections`, is usually okay. --- ## Name events correctly · CS-05.12 · **MUST** Name events with a verb or a verb phrase, such as `Click`, `Deleted`, `Closing`, `Minimizing`, and `Arriving`. For example, the declaration of the Search event may look like this: ```csharp public event EventHandler Search; ``` For events that occur before or after something (pre and post events), use the `ing` and `ed` suffixes respectively. For example, a close event that is raised before a window is closed would be called `Closing` and one that is raised after the window is closed would be called `Closed`. Don't use `Before` or `After` prefixes or suffixes to indicate pre and post events. Suppose you want to define events related to the deletion process of an object. Define those events as follows: * `Deleting`: Occurs just before the object is getting deleted * `Delete`: Occurs when the object needs to be deleted by the event handler. * `Deleted`: Occurs when the object is already deleted. --- ## Prefix an event handler with `On` · CS-05.13 · **MUST** It is good practice to prefix the method that handles an event with `On`. For example, a method that handles the `Closing` event could be named `OnClosing`. **Roslyn Analyzer Rule [AV1738](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1738-prefix-an-event-handler-with-on-)** --- ## Use an underscore for irrelevant lambda parameters · CS-05.14 · **MUST** If you use a lambda statement, for instance, to subscribe to an event, and the actual parameters of the event are irrelevant, use the following convention to make that more explicit. ```csharp button.Click += (_, __) => HandleClick(); ``` **Roslyn Analyzer Rule [AV1739](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1739-use-an-underscore-for-irrelevant-lambda-parameters-)** --- ## Group extension methods in a class suffixed with `Extensions` · CS-05.15 · **MUST** If the name of an extension method conflicts with another member or extension method, you must prefix the call with the class name. Having them in a dedicated class with the `Extensions` suffix improves readability. **Roslyn Analyzer Rule [AV1745](https://github.com/bkoelman/CSharpGuidelinesAnalyzer/blob/master/docs/Overview.md#av1745-group-extension-methods-in-a-class-suffixed-with-extensions-)** --- ## Postfix asynchronous methods with `Async` or `TaskAsync` · CS-05.16 · **MUST** The general convention for methods that return `Task` or `Task` is to post-fix them with `Async`, but if such a method already exist, use `TaskAsync` instead. **Roslyn Analyzer Rules [RCS1046](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1046/) and [ACL1005](https://github.com/audaciaconsulting/Audacia.CodeAnalysis/blob/master/dotnet-roslyn/analyzers/Audacia.CodeAnalysis.Analyzers/README.md#acl1005---asynchronous-method-name-is-not-suffixed-with-async)** ## Avoid using synonyms of the word "Data" in entity names · CS-05.17 · **Should** When creating an entity, words such as "Data", "Information", "Fields" etc. should be avoided as they don't add any explanatory value.