--- title: Getting Started with C# Eval Expression | daily.dev description: This tutorial introduces the C# Eval Expression Library, a NuGet package (Z.Expressions.Eval) that extends LINQ with runtime dynamic capabilities. It covers... canonical: https://daily.dev/posts/getting-started-with-c-eval-expression-3doyghkml twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Getting Started with C# Eval Expression | daily.dev og:description: This tutorial introduces the C# Eval Expression Library, a NuGet package (Z.Expressions.Eval) that extends LINQ with runtime dynamic capabilities. It covers... og:url: https://daily.dev/posts/getting-started-with-c-eval-expression-3doyghkml og:image: https://api.daily.dev/og/posts/3doYghkml.png og:image:alt: Getting Started with C# Eval Expression og:image:width: 1200 og:image:height: 630 og:locale: 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. # Getting Started with C# Eval Expression **[NikolaTech](https://daily.dev/sources/nikolatech)** · 6 min read · 0 upvotes · 0 comments ## Summary This tutorial introduces the C# Eval Expression Library, a NuGet package (Z.Expressions.Eval) that extends LINQ with runtime dynamic capabilities. It covers Eval.Execute for running arbitrary C# expressions at runtime (with variable passing via anonymous objects, dictionaries, class instances, and ExpandoObject), EvalContext for restricting and securing dynamic code execution, and LINQ extension methods like WhereDynamic, OrderByDynamic, and Execute for building dynamic filtering and sorting queries that translate to SQL when used with IQueryable/Entity Framework Core. Code examples demonstrate filtering products by price, combining dynamic where/order clauses, and configuring safe execution contexts. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I filter a LINQ query dynamically at runtime in C#? Use the WhereDynamic extension method from the C# Eval Expression library, which generates the proper lambda expression internally and calls the standard LINQ Where method. You can pass the expression either as a string inside a lambda, like x => "x.Price <= 50", or as a full string, like "x => x.Price <= 50" - both are equally supported. _daily.dev surfaces practical patterns like dynamic LINQ filtering for developers building flexible query features._ ### How can I safely execute arbitrary C# expressions at runtime without exposing security risks? Use EvalContext with SafeMode enabled and UnregisterAll() to clear default registrations, then explicitly register only the types, aliases, and variables you consider safe using RegisterDefaultAliasSafe(), RegisterType(), and RegisterLocalVariable(). This restricts what code can run inside dynamically evaluated expressions, preventing access to unintended types or members. _Developers securing dynamic code execution can find setup details like this through daily.dev._ ## Similar posts on daily.dev - [Expression Trees as a Reflection Alternative in C\#: When to Switch](https://daily.dev/posts/expression-trees-as-a-reflection-alternative-in-c-when-to-switch-xi1rcodvd) · We Are .NET · 3 upvotes · 0 comments - [.NET 11 Preview for .NET MAUI: Simplify XAML with Inline C\# Expressions](https://daily.dev/posts/net-11-preview-for-net-maui-simplify-xaml-with-inline-c-expressions-j8nlhot3a) · Syncfusion · 0 upvotes · 0 comments - [The best new features of C\# 14](https://daily.dev/posts/the-best-new-features-of-c-14-6gsbbjwv4) · InfoWorld · 46 upvotes · 4 comments - [LINQ in C\#](https://daily.dev/posts/linq-in-c--eoxkvhpkr) · C\# Corner · 36 upvotes · 2 comments - [Goodbye ValueConverters, Hello C\# Expressions in .NET MAUI](https://daily.dev/posts/goodbye-valueconverters-hello-c-expressions-in-net-maui-ceemfeu0j) · Telerik · 6 upvotes · 0 comments --- Tags: [#.net](https://daily.dev/tags/.net), [#c#](https://daily.dev/tags/c#) [View this post on daily.dev](https://daily.dev/posts/getting-started-with-c-eval-expression-3doyghkml) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Getting Started with C# Eval Expression","url":"https://daily.dev/posts/getting-started-with-c-eval-expression-3doyghkml","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/getting-started-with-c-eval-expression-3doyghkml"},"datePublished":"2026-10-04T13:06:59.309Z","dateModified":"2026-10-04T13:13:07.868Z","description":"This tutorial introduces the C# Eval Expression Library, a NuGet package (Z.Expressions.Eval) that extends LINQ with runtime dynamic capabilities. 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