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Q&A C#: Performance hit from using calculated property instead of get-only property with initializer?

You're right about the recalculation, as you can see from some easy experimentation by rigging two (dynamic) properties and logging what each one gives you. public long TimeStamp1 { get; } = DateT...

posted 20d ago by Michael‭ · edited 20d ago by Michael‭

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#2: Post edited by

Michael‭ · 2024-10-28T16:39:04Z (20 days ago)
JetBrains has different tools than I remember

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You're right about the recalculation, as you can see from some easy experimentation by rigging two (dynamic) properties and logging what each one gives you.
```csharp
public long TimeStamp1 { get; } = DateTime.Now.Ticks;
public long TimeStamp2 => DateTime.Now.Ticks;
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
```
My personal suspicion is that ReSharper thinks most people *meant* to have dynamic resolution of the property getter. ReSharper would then expect people to be *surprised* to discover that the initial value is never changed. [Alexei notes][alexei] that "if you want to store the initial evaluation result, define a `static readonly` field instead to better convey the meaning (it is not supposed to change)."
[alexei]: https://software.codidact.com/comments/thread/10248#comment-25685

You're right about the recalculation, as you can see from some easy experimentation by rigging two (dynamic) properties and logging what each one gives you.
```csharp
public long TimeStamp1 { get; } = DateTime.Now.Ticks;
public long TimeStamp2 => DateTime.Now.Ticks;
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
```
My personal suspicion is that Rider thinks most people *meant* to have dynamic resolution of the property getter. Rider would then expect people to be *surprised* to discover that the initial value is never changed. [Alexei notes][alexei] that "if you want to store the initial evaluation result, define a `static readonly` field instead to better convey the meaning (it is not supposed to change)."
[alexei]: https://software.codidact.com/comments/thread/10248#comment-25685

#1: Initial revision by

Michael‭ · 2024-10-28T16:37:28Z (20 days ago)

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You're right about the recalculation, as you can see from some easy experimentation by rigging two (dynamic) properties and logging what each one gives you.

```csharp
public long TimeStamp1 { get; } = DateTime.Now.Ticks;
public long TimeStamp2 => DateTime.Now.Ticks;

Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
Thread.Sleep(3000);
Console.Log(Foo.TimeStamp1);
Console.Log(Foo.TimeStamp2);
```

My personal suspicion is that ReSharper thinks most people *meant* to have dynamic resolution of the property getter. ReSharper would then expect people to be *surprised* to discover that the initial value is never changed. [Alexei notes][alexei] that "if you want to store the initial evaluation result, define a `static readonly` field instead to better convey the meaning (it is not supposed to change)."

[alexei]: https://software.codidact.com/comments/thread/10248#comment-25685

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