FieldAccessor Class

public sealed class FieldAccessor : MemberAccessor

using System;
using System.Reflection;
using System.Runtime.Versioning;

using KGySoft.Diagnostics;
using KGySoft.Reflection;

class Example
{
    private class TestClass
    {
        public int TestField;
    }

    private static string PlatformName => ((TargetFrameworkAttribute)Attribute.GetCustomAttribute(Assembly.GetExecutingAssembly(),
        typeof(TargetFrameworkAttribute))).FrameworkDisplayName;

    static void Main(string[] args)
    {
        var instance = new TestClass();
        FieldInfo field = instance.GetType().GetField(nameof(TestClass.TestField));
        FieldAccessor accessor = FieldAccessor.GetAccessor(field);

        new PerformanceTest { TestName = $"Set Field - {PlatformName}", Iterations = 1_000_000 }
            .AddCase(() => instance.TestField = 1, "Direct set")
            .AddCase(() => field.SetValue(instance, 1), "System.Reflection.FieldInfo.SetValue")
            .AddCase(() => accessor.Set(instance, 1), "FieldAccessor.Set")
            .AddCase(() => accessor.SetInstanceValue(instance, 1), "FieldAccessor.SetInstanceValue<,>")
            .DoTest()
            .DumpResults(Console.Out);

        new PerformanceTest<int> { TestName = $"Get Field - {PlatformName}", Iterations = 1_000_000 }
            .AddCase(() => instance.TestField, "Direct get")
            .AddCase(() => (int)field.GetValue(instance), "System.Reflection.FieldInfo.GetValue")
            .AddCase(() => (int)accessor.Get(instance), "FieldAccessor.Get")
            .AddCase(() => accessor.GetInstanceValue<TestClass, int>(instance), "FieldAccessor.GetInstanceValue<,>")
            .DoTest()
            .DumpResults(Console.Out);
    }
}

// This code example produces a similar output to these ones:

// ==[Set Field - .NET 8.0 Results]================================================
// Iterations: 1,000,000
// Warming up: Yes
// Test cases: 4
// Calling GC.Collect: Yes
// Forced CPU Affinity: No
// Cases are sorted by time (quickest first)
// --------------------------------------------------
// 1. Direct set: average time: 2.83 ms
// 2. FieldAccessor.SetInstanceValue<,>: average time: 4.53 ms (+1.71 ms / 160.31%)
// 3. FieldAccessor.Set: average time: 10.84 ms (+8.01 ms / 383.41%)
// 4. System.Reflection.FieldInfo.SetValue: average time: 52.15 ms (+49.33 ms / 1,844.55%)
// 
// ==[Get Field - .NET 8.0 Results]================================================
// Iterations: 1,000,000
// Warming up: Yes
// Test cases: 4
// Calling GC.Collect: Yes
// Forced CPU Affinity: No
// Cases are sorted by time (quickest first)
// --------------------------------------------------
// 1. Direct get: average time: 2.83 ms
// 2. FieldAccessor.GetInstanceValue<,>: average time: 3.75 ms (+0.92 ms / 132.42%)
// 3. FieldAccessor.Get: average time: 10.18 ms (+7.35 ms / 359.81%)
// 4. System.Reflection.FieldInfo.GetValue: average time: 54.13 ms (+51.30 ms / 1,913.66%)

// ==[Set Field - .NET Framework 4.8 Results]================================================
// Iterations: 1,000,000
// Warming up: Yes
// Test cases: 4
// Calling GC.Collect: Yes
// Forced CPU Affinity: No
// Cases are sorted by time (quickest first)
// --------------------------------------------------
// 1. Direct set: average time: 3.11 ms
// 2. FieldAccessor.SetInstanceValue<,>: average time: 11.45 ms (+8.34 ms / 367.99%)
// 3. FieldAccessor.Set: average time: 13.65 ms (+10.54 ms / 438.45%)
// 4. System.Reflection.FieldInfo.SetValue: average time: 99.95 ms (+96.84 ms / 3,211.03%)
// 
// ==[Get Field - .NET Framework 4.8 Results]================================================
// Iterations: 1,000,000
// Warming up: Yes
// Test cases: 4
// Calling GC.Collect: Yes
// Forced CPU Affinity: No
// Cases are sorted by time (quickest first)
// --------------------------------------------------
// 1. Direct get: average time: 2.15 ms
// 2. FieldAccessor.GetInstanceValue<,>: average time: 10.24 ms (+8.09 ms / 476.41%)
// 3. FieldAccessor.Get: average time: 10.56 ms (+8.41 ms / 491.29%)
// 4. System.Reflection.FieldInfo.GetValue: average time: 75.45 ms (+73.30 ms / 3,509.27%)