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Use expression body for constructors (IDE0021)

  • Article
Property Value
Rule ID IDE0021
Title Use expression body for constructors
Category Style
Subcategory Language rules (expression-bodied members)
Applicable languages C#
Options csharp_style_expression_bodied_constructors

Overview

This style rule concerns the use of expression bodies versus block bodies for constructors.

Options

Set the value of the associated option for this rule to specify whether expression bodies or block bodies for constructors are preferred, and if expression bodies are preferred, whether they're preferred only for single-line expressions.

For more information about configuring options, see Option format.

csharp_style_expression_bodied_constructors

Property Value Description
Option name csharp_style_expression_bodied_constructors
Option values true Prefer expression bodies for constructors
when_on_single_line Prefer expression bodies for constructors when they will be a single line
false Prefer block bodies for constructors
Default option value false 
// csharp_style_expression_bodied_constructors = true
public Customer(int age) => Age = age;

// csharp_style_expression_bodied_constructors = false
public Customer(int age) { Age = age; }

Suppress a warning

If you want to suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable IDE0021
// The code that's violating the rule is on this line.
#pragma warning restore IDE0021

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.IDE0021.severity = none

To disable all of the code-style rules, set the severity for the category Style to none in the configuration file.

[*.{cs,vb}]
dotnet_analyzer_diagnostic.category-Style.severity = none

For more information, see How to suppress code analysis warnings.

See also