Use conditional expression for assignment (IDE0045)

Property Value
Rule ID IDE0045
Title Use conditional expression for assignment
Category Style
Subcategory Language rules (expression-level preferences)
Applicable languages C# and Visual Basic
Introduced version Visual Studio 2017 version 15.8
Options dotnet_style_prefer_conditional_expression_over_assignment


This style rule concerns the use of a ternary conditional expression versus an if-else statement for assignments that require conditional logic.


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


Property Value Description
Option name dotnet_style_prefer_conditional_expression_over_assignment
Option values true Prefer assignments with a ternary conditional
false Prefer assignments with an if-else statement
Default option value true
// dotnet_style_prefer_conditional_expression_over_assignment = true
string s = expr ? "hello" : "world";

// dotnet_style_prefer_conditional_expression_over_assignment = false
string s;
if (expr)
    s = "hello";
    s = "world";
' dotnet_style_prefer_conditional_expression_over_assignment = true
Dim s As String = If(expr, "hello", "world")

' dotnet_style_prefer_conditional_expression_over_assignment = false
Dim s As String
If expr Then
    s = "hello"
    s = "world"
End If

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 IDE0045
// The code that's violating the rule is on this line.
#pragma warning restore IDE0045

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

dotnet_diagnostic.IDE0045.severity = none

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

dotnet_analyzer_diagnostic.category-Style.severity = none

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

See also