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Update AV1546: Prefer interpolated strings over concatenation or string.Format. #365

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Update AV1546: Prefer interpolated strings over concatenation or string.Format. #365

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4 changes: 3 additions & 1 deletion _rules/1546.md
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ rule_category: maintainability
title: Prefer interpolated strings over concatenation or `string.Format`.
severity: 1
---
Since .NET 6, interpolated strings are optimized at compile-time, which inlines constants and reduces memory allocations due to boxing and string copying.
Since .NET 6, interpolated strings are optimized at compile-time, which inlines constants and reduces memory allocations due to boxing and string copying. In .NET 8 and later, interpolated strings are further optimized using `DefaultInterpolatedStringHandler`, making them the fastest option in most scenarios.

// GOOD
string result = $"Welcome, {firstName} {lastName}!";
Expand All @@ -17,3 +17,5 @@ Since .NET 6, interpolated strings are optimized at compile-time, which inlines

// BAD
string result = string.Concat("Welcome, ", firstName, " ", lastName, "!");

For building strings in loops or with many parts, consider using `StringBuilder` or raw string literals (C# 11+) when appropriate.
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@bkoelman bkoelman Mar 29, 2026

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How would using raw string literals help in loops?