C
C#•3y ago
Bobby Bob

Static vs Non-Static classes [Answered]

Please see here for the detailed question and all of the relevant code: https://gist.github.com/blueboy90780/f67813131e7a568d7998fcfea1166bd3
Gist
Used for comparing Static and Non-Static access to static fields
Used for comparing Static and Non-Static access to static fields - NonStaticClass.cs
23 Replies
Bobby Bob
Bobby BobOP•3y ago
I've asked my question underneath as a comment, it's hard to articulate this question without code context so a gist is used instead
TheBoxyBear
TheBoxyBear•3y ago
A static member is not tied to any instance of the class so when accessed internally by an instance, the same static values are shared. You can also access it from outside the class without using an instance A static class forces every member to be static and as a result, you also can't create instances of that class Making a method static can be useful to denote that it doesn't reference instance members. A good use of static method is for creating objects where a constructor doesn't make sense such as Image.FromFile() or Color.FromArgb()
Bobby Bob
Bobby BobOP•3y ago
Wait seriously? So even if I don't explicitly give the static keyword to all my members, they default to static? Ah, thank you that's pretty good
TheBoxyBear
TheBoxyBear•3y ago
You need to explicitely define everything as static in a static class It won't compile if any member is not static
Bobby Bob
Bobby BobOP•3y ago
Ooooo Thank you this clarified a lot Btw when should you use a static method over a non-static method? If a non-static method is able do everything that a static method is able to do and more, then why should we ever use static method? Is there a functional reason beyond just a syntactical indicator?
arion
arion•3y ago
Static Constructors are a little different than usual static members, its closer to the readonly keyword Notably, they're called before the first instance (if any) or right before something references it. What they mean by "references" is using something from that class anywhere in your code. Example: calling a method, creating a new instance, etc A static constructor can be created in a static or non-static class. More info here: https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/static-constructors The performance between the two are negligible (around 9% faster when i tested in favor of statics) Static vs non-static is based on "Do I need more of this?" or "Does my class inherit anything special" If you have some file manager that only exists once, then static is the likely bet If you have something such as a File A File can have a few methods like - Delete - Move - Current Directory - Parent Directory - Get Files (Returns a Collection of Files) Regarding "Does my class inherit anything special", Unity implements this using Monobehaviours If a non-static method doesn't reference anything in your instance, you might want to consider making it static. An example of this would be 
public void SayHello()
{
  Console.WriteLine("Hello there!");
}
public void SayHello()
{
  Console.WriteLine("Hello there!");
}
Some class instances are automatically created behind the scenes, for example 
string s = "Hello!";
int number = 7;
string s = "Hello!";
int number = 7;
Bobby Bob
Bobby BobOP•3y ago
9% faster is still % faster, so I think I'll be using static whenever it makes sense What can static methods do that non-static methods can't do? Like what would be the purpose?
sibber
sibber•3y ago
its definitely not 9% faster where did you get that number my general rule of thumb is if a method doesnt need any instance members, make it static
becquerel
becquerel•3y ago
You can use a static method without creating an instance of the relevant class. There are cases where this is useful, e.g. factory methods: 
public class MyObject
{
  // Private constructor. Other classes can't create MyObject directly.
  private MyObject() {}

  // Expose static method that handles creating the object.
  // Because it's not a constructor, it can be async,
  // have out variables, etc.
  public static async Task<MyObject> Create(string someArgument)
  {
    var obj = new MyObject();

    await DoSomethingAsync(someArgument);
  }
}

// elsewhere

var obj = await MyObject.Create("hello world");
public class MyObject
{
  // Private constructor. Other classes can't create MyObject directly.
  private MyObject() {}

  // Expose static method that handles creating the object.
  // Because it's not a constructor, it can be async,
  // have out variables, etc.
  public static async Task<MyObject> Create(string someArgument)
  {
    var obj = new MyObject();

    await DoSomethingAsync(someArgument);
  }
}

// elsewhere

var obj = await MyObject.Create("hello world");
more generally you can think of using/not using static methods as engaging with OOP or not. sometimes it's useful to model your problem or program in terms of OOP, in which case you don't need static much - other times OOP just gets in your way and you want to 'turn it off' Generally I veer away from using static because I find it to be a code smell. It encourages massive methods where you pass around fifty parameters, rather than just having a class with some state
Pobiega
Pobiega•3y ago
Extension methods are only allowed to be created in a static class, and are always static methods - so thats a pretty common usecase.
becquerel
becquerel•3y ago
extension everything when PepeHands
arion
arion•3y ago
benchmark dotnet extension events and properties getting no love, gotta make them by hand <a:AA_Satania_Cry:599145877071724555>
sibber
sibber•3y ago
and you got 9%? wow
Bobby Bob
Bobby BobOP•3y ago
9% is still 9% which is pretty good
sibber
sibber•3y ago
these are my results: 
|        Method |     Mean |   Error |  StdDev | Ratio |
|-------------- |---------:|--------:|--------:|------:|
| NonStaticCall | 305.3 us | 0.44 us | 0.41 us |  1.00 |
|    StaticCall | 305.0 us | 0.51 us | 0.48 us |  1.00 |

// * Legends *
  Mean   : Arithmetic mean of all measurements
  Error  : Half of 99.9% confidence interval
  StdDev : Standard deviation of all measurements
  Ratio  : Mean of the ratio distribution ([Current]/[Baseline])
  1 us   : 1 Microsecond (0.000001 sec)
|        Method |     Mean |   Error |  StdDev | Ratio |
|-------------- |---------:|--------:|--------:|------:|
| NonStaticCall | 305.3 us | 0.44 us | 0.41 us |  1.00 |
|    StaticCall | 305.0 us | 0.51 us | 0.48 us |  1.00 |

// * Legends *
  Mean   : Arithmetic mean of all measurements
  Error  : Half of 99.9% confidence interval
  StdDev : Standard deviation of all measurements
  Ratio  : Mean of the ratio distribution ([Current]/[Baseline])
  1 us   : 1 Microsecond (0.000001 sec)
sibber
sibber•3y ago
https://paste.mod.gg/bizzhutqjbwf/0
BlazeBin - bizzhutqjbwf
A tool for sharing your source code with the world!
sibber
sibber•3y ago
on a 5600x so on other hardware it might be 9% slower but that would be microseconds in difference, which is practically nothing
arion
arion•3y ago
did a similar test 
|       Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| InstanceTest |           .NET 6.0 |           .NET 6.0 |       NA |      NA |      NA |     ? |       ? |
|   StaticTest |           .NET 6.0 |           .NET 6.0 |       NA |      NA |      NA |     ? |       ? |
|              |                    |                    |          |         |         |       |         |
| InstanceTest | .NET Framework 4.8 | .NET Framework 4.8 | 401.6 ns | 8.05 ns | 8.27 ns |  1.00 |    0.00 |
|   StaticTest | .NET Framework 4.8 | .NET Framework 4.8 | 380.8 ns | 4.45 ns | 4.16 ns |  0.95 |    0.02 |

|       Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| InstanceTest |           .NET 6.0 |           .NET 6.0 | 491.3 ns | 9.06 ns | 8.03 ns |  1.00 |    0.00 |
|   StaticTest |           .NET 6.0 |           .NET 6.0 | 393.8 ns | 3.93 ns | 3.49 ns |  0.80 |    0.02 |
|              |                    |                    |          |         |         |       |         |
| InstanceTest | .NET Framework 4.8 | .NET Framework 4.8 |       NA |      NA |      NA |     ? |       ? |
|   StaticTest | .NET Framework 4.8 | .NET Framework 4.8 |       NA |      NA |      NA |     ? |       ? |
|       Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| InstanceTest |           .NET 6.0 |           .NET 6.0 |       NA |      NA |      NA |     ? |       ? |
|   StaticTest |           .NET 6.0 |           .NET 6.0 |       NA |      NA |      NA |     ? |       ? |
|              |                    |                    |          |         |         |       |         |
| InstanceTest | .NET Framework 4.8 | .NET Framework 4.8 | 401.6 ns | 8.05 ns | 8.27 ns |  1.00 |    0.00 |
|   StaticTest | .NET Framework 4.8 | .NET Framework 4.8 | 380.8 ns | 4.45 ns | 4.16 ns |  0.95 |    0.02 |

|       Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| InstanceTest |           .NET 6.0 |           .NET 6.0 | 491.3 ns | 9.06 ns | 8.03 ns |  1.00 |    0.00 |
|   StaticTest |           .NET 6.0 |           .NET 6.0 | 393.8 ns | 3.93 ns | 3.49 ns |  0.80 |    0.02 |
|              |                    |                    |          |         |         |       |         |
| InstanceTest | .NET Framework 4.8 | .NET Framework 4.8 |       NA |      NA |      NA |     ? |       ? |
|   StaticTest | .NET Framework 4.8 | .NET Framework 4.8 |       NA |      NA |      NA |     ? |       ? |
on a 3600 https://gist.github.com/5b472e01fb7228f2fe2d8814c5f62833 I was unable to replicate yours since NonStaticTestClass wasn't included in the paste nor referenced within the benchmark the ? | ? is the change from frameworks (2 separate projects using the same code)
sibber
sibber•3y ago
I was unable to replicate yours since NonStaticTestClass wasn't included in the paste nor referenced within the benchmark
oops i was testing something forgot to remove that the benchmark doesnt use that
arion
arion•3y ago
gotcha, i'll try pasting the test without that class real quick then
sibber
sibber•3y ago
oh you were testing fields but yeah either way the difference in performance is negligible
arion
arion•3y ago
Ran your test just now and its similar to your results 
|        Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|-------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| NonStaticCall |           .NET 6.0 |           .NET 6.0 | 403.4 us | 6.50 us | 6.08 us |  1.00 |    0.00 |
|    StaticCall |           .NET 6.0 |           .NET 6.0 | 401.7 us | 7.35 us | 6.88 us |  1.00 |    0.02 |
| NonStaticCall | .NET Framework 4.8 | .NET Framework 4.8 | 426.5 us | 2.12 us | 1.99 us |  1.00 |    0.00 |
|    StaticCall | .NET Framework 4.8 | .NET Framework 4.8 | 424.3 us | 2.74 us | 2.56 us |  0.99 |    0.01 |
|        Method |                Job |            Runtime |     Mean |   Error |  StdDev | Ratio | RatioSD |
|-------------- |------------------- |------------------- |---------:|--------:|--------:|------:|--------:|
| NonStaticCall |           .NET 6.0 |           .NET 6.0 | 403.4 us | 6.50 us | 6.08 us |  1.00 |    0.00 |
|    StaticCall |           .NET 6.0 |           .NET 6.0 | 401.7 us | 7.35 us | 6.88 us |  1.00 |    0.02 |
| NonStaticCall | .NET Framework 4.8 | .NET Framework 4.8 | 426.5 us | 2.12 us | 1.99 us |  1.00 |    0.00 |
|    StaticCall | .NET Framework 4.8 | .NET Framework 4.8 | 424.3 us | 2.74 us | 2.56 us |  0.99 |    0.01 |
though yeah, sadly there's no conclusive test (without running a million different scenarios) to test static vs instance but yeah, still negligible
Accord
Accord•3y ago
✅ This post has been marked as answered!

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