There are a lot of warnings regarding the speed of using Reflection in .Net. For sorting a datagridview by column Datapropertyname I made a short test program which shows Linq Sort by Reflection is faster then by Member. I am not sure if I all have done correctly and ask the community for a review.
class Program {
private static Random random = new Random();
class TestClass {
public string Name { get; set; }
public int Number { get; set; }
}
static string RandomString(int length) {
const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
return new string(Enumerable.Repeat(chars, length)
.Select(s => s[random.Next(s.Length)]).ToArray());
}
static void SortyByReflection(List<TestClass> testlst) {
PropertyInfo prop = typeof(TestClass).GetProperties().Where(p => p.Name == "Name").FirstOrDefault();
List<TestClass> sorted = testlst.OrderBy(o => prop.GetValue(o)).ToList();
}
static void SortByMember(List<TestClass> testlst) {
List<TestClass> sorted = testlst.OrderBy(o => o.Name).ToList();
}
delegate void dRunner(List<TestClass> testlst);
static long UsedTime(dRunner testDelegate, List<TestClass> testlst) {
Stopwatch timer = new Stopwatch();
timer.Start();
testDelegate(testlst);
timer.Stop();
return timer.ElapsedTicks;
}
static void Main(string[] args) {
// make a dry run to init the program
SortByMember(new List<TestClass>());
SortyByReflection(new List<TestClass>());
List<int> lstSize = new List<int> { 100, 1000, 10000, 100000 };
foreach (int count in lstSize) {
// Init List
List<TestClass> testlst = new List<TestClass>();
for (int i = 0; i < count; i++) {
testlst.Add(new TestClass { Name = RandomString(10), Number = i });
}
List<long> reflection = new List<long>();
List<long> memberTime = new List<long>();
for (int i = 0; i < 100; i++) {
reflection.Add(UsedTime(SortyByReflection,testlst));
memberTime.Add(UsedTime(SortByMember,testlst));
}
Console.WriteLine($"{reflection.Min()} / {reflection.Max()} / {reflection.Average()} Min/ Max / Average Ticks needed for Reflection {count} size");
Console.WriteLine($"{memberTime.Min()} / {memberTime.Max()} / {memberTime.Average()} Min/ Max / Average Ticks needed for Member {count} size");
Console.WriteLine(new string('-', 80));
}
Console.WriteLine("done");
Console.ReadLine();
}
/*
* Sample output
425 / 1837 / 539,75 Min/ Max / Average Ticks needed for Reflection 100 size
479 / 1265 / 605,14 Min/ Max / Average Ticks needed for Member 100 size
--------------------------------------------------------------------------------
6251 / 11819 / 7309,82 Min/ Max / Average Ticks needed for Reflection 1000 size
7164 / 13369 / 8201,42 Min/ Max / Average Ticks needed for Member 1000 size
--------------------------------------------------------------------------------
76214 / 103169 / 82003,53 Min/ Max / Average Ticks needed for Reflection 10000 size
86139 / 121152 / 93201,55 Min/ Max / Average Ticks needed for Member 10000 size
--------------------------------------------------------------------------------
1092454 / 1188244 / 1139228,26 Min/ Max / Average Ticks needed for Reflection 100000 size
1225469 / 1353753 / 1280549,37 Min/ Max / Average Ticks needed for Member 100000 size
--------------------------------------------------------------------------------
done
*/
}
The Average is always around 10% faster when using Reflection.
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