--- title: "Liskov Substitution Principle C#: Correct Inheritance Every Time" url: https://daily.dev/posts/liskov-substitution-principle-c-correct-inheritance-every-time-t6mye5vlw source_url: https://www.devleader.ca/2026/06/13/liskov-substitution-principle-c-correct-inheritance-every-time type: article source: "We Are .NET" published: 2026-06-13T22:22:33.085Z updated: 2026-06-13T22:22:56.753Z tags: ["general-programming", "c#", "design-patterns"] reading_time: 15 upvotes: 2 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Liskov Substitution Principle C#: Correct Inheritance Every Time **[We Are .NET](https://daily.dev/sources/wearedotnet)** · 15 min read · 2 upvotes · 0 comments ## Summary A thorough guide to the Liskov Substitution Principle (LSP) in C#, covering behavioral contracts (preconditions, postconditions, invariants) rather than just type signatures. Uses the classic Rectangle/Square violation to illustrate how mutable inheritance breaks postconditions, then shows fixes via shared interfaces and immutable records. Also covers NotImplementedException as an LSP signal, interface segregation as a remedy, and how structural patterns like Proxy, Decorator, Iterator, and Chain of Responsibility all depend on LSP correctness. Practical design rules include favoring sealed classes, immutability, small interfaces, documented contracts, and running base-type tests against all subtypes. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Liskov Substitution Principle](https://daily.dev/posts/liskov-substitution-principle-nt8k1h6hv) · Ruby Flow · 1 upvotes · 0 comments - [A SOLID Load of Bull](https://daily.dev/posts/a-solid-load-of-bull-hw6sdv1co) · Lobsters · 23 upvotes · 2 comments - [SOLID Violations C\#: How to Recognize and Fix Each One](https://daily.dev/posts/solid-violations-c-how-to-recognize-and-fix-each-one-jb3sdnwow) · We Are .NET · 0 upvotes · 0 comments --- Tags: [#general-programming](https://daily.dev/tags/general-programming), [#c#](https://daily.dev/tags/c#), [#design-patterns](https://daily.dev/tags/design-patterns) [View this post on daily.dev](https://daily.dev/posts/liskov-substitution-principle-c-correct-inheritance-every-time-t6mye5vlw)