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Prefer 'null' check over type check (IDE0150)

  • Article
Property Value
Rule ID IDE0150
Title Prefer null check over type check
Category Style
Subcategory Language rules (expression-level preferences)
Applicable languages C#
Options csharp_style_prefer_null_check_over_type_check

Overview

This style rule flags use of the is {type} statement when is not null can be used instead. Similarly, it flags use of the is not {type} statement in favor of is null. Using is null or is not null improves code readability.

Options

Options specify the behavior that you want the rule to enforce. For information about configuring options, see Option format.

csharp_style_prefer_null_check_over_type_check

Property Value Description
Option name csharp_style_prefer_null_check_over_type_check
Option values true Prefer null check over type check.
false Disables the rule.
Default option value true

Example

// Violates IDE0150.
if (numbers is not IEnumerable<int>) ...

// Fixed code.
if (numbers is null) ...

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 IDE0150
// The code that's violating the rule is on this line.
#pragma warning restore IDE0150

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

[*.{cs,vb}]
dotnet_diagnostic.IDE0150.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