code_learner52 · 09.05.2026

Why use Expression<Func<T>> instead of Func<T> in C#? Explain with examples

Hello everyone! I started learning C# and came across this construct: `Expression>`. I understand that `Func` is just a delegate that can be invoked. But why wrap it in `Expression<>`? It seems like you could just pass a lambda as `Func` and call it when needed.\n\nFor example, in Entity Framework, I've seen that methods like `.Where()` often use `Expression>`. But if I write `.Where(x => x.Age > 18)`, the compiler automatically substitutes the correct type. Why do I need to explicitly specify `Expression<>`?\n\nI have this code:\n\n```csharp\nFunc square = x => x * x;\nConsole.WriteLine(square(5)); // 25\n```\n\nAnd this:\n\n```csharp\nExpression> squareExpr = x => x * x;\n// How to use this? You can't just call it.\n```\n\nI understand that `Exp

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