CODEWITHSUNDEEP
c#reflection
Liang Wu
Liang Wu

Reputation: 1822

Static Reflection Performance

I am playing about the static reflection code from Joel Abrahamsson's blog and Daniel Cazzulino's blog. But I found their performance is kind of slow, even comparing with refection using "magic string". 

int iterations = 1000000; 
watch.Start();

for (int i = 0; i < iterations; i++)
{
    var propertyOfName = Reflect<Employee>.GetProperty(c => c.Name); 
}

watch.Stop();
Console.WriteLine("[Reflector]: " + watch.ElapsedMilliseconds.ToString());
watch.Reset();
watch.Start();

for (int i = 0; i < iterations; i++)
{
    var propertyName = typeof (Employee).GetProperty("Name"); 
}

watch.Stop();
Console.WriteLine("[Regular Reflection]: " + watch.ElapsedMilliseconds.ToString());
watch.Reset();
watch.Start();

for (int i = 0; i < iterations; i++)
{
    var propertyName = StaticReflection.GetMemberName<Employee>(c => c.Name);
}

watch.Stop();
Console.WriteLine("[StaticReflection]: " + watch.ElapsedMilliseconds.ToString());

Here is the result:

So why should we prefer Static Reflection? Just remove "magic string"? Or we should add some caching to improve static reflection performance?

Upvotes: 9

Views: 2384

Answers (2)

Michael Freidgeim
Michael Freidgeim

Reputation: 28435

Have you seen http://ayende.com/blog/779/static-reflection ? He was using just delegates (not expression trees) and had improved compare to normal Reflection performance.

Example of the implementation

 public static MethodInfo MethodInfo<TRet, A0>(Func<TRet, A0> func0)
{
        return func0.Method;
}

Upvotes: 2

Marc Gravell
Marc Gravell

Reputation: 1062745

The main reason to "prefer" it would be static type checking by the compiler, to ensure you don't make a mess of it (and to ensure it works if you obfuscate, for example). However, IMO it is so rare that a typo here is a significant bug (meaning: I'm not including the brain-dead typo you spot and fix during development / unit-testing); so (since I am a performance nut) I typically advise to use the simplest option (string). A particular example of this is when people are implementing the INotifyPropertyChanged interface using tricks like this. Just pass a string ;p

Upvotes: 4

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