API

Avoid FormattableString

Docs > Code Analysis > Static Analysis Rules > Avoid FormattableString

Metadata

ID: csharp-best-practices/avoid-formattablestring

Language: C#

Severity: Info

Category: Performance

Description

The function string.Create prevents unnecessary allocations. It should be preferred over FormattableString functions.

Learn More

Creating Strings with no allocation overhead using String.Create

Non-Compliant Code Examples

class MyClass {
    public static void myFunction(string s)
    {
        Console.WriteLine(FormattableString.CurrentCulture("foobar"));
        Console.WriteLine(FormattableString.Invariant($"Counter: {(int)counter}"));
    }
}

Compliant Code Examples

class MyClass {
    public static void myFunction(string s)
    {
        Console.WriteLine(string.Create(CultureInfo.CurrentCulture, "foobar"));
        Console.WriteLine(string.Create(CultureInfo.InvariantCulture, $"Counter: {(int)counter}"));
    }
}

How to use this rule

1
2
rulesets:
  - csharp-best-practices     # Rules to enforce C# best practices.

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