属性——Property，由get,set访问器组成，这是C#使用度比较高的类成员。今天分几组对比测试，来看一下使用Property的性能。
被测试对象：
public class MyClass
{private string _myProperty1 = DateTime.Now.ToString();public string MyProperty1 { get { return _myProperty1; } }public string MyProperty2 { get { return DateTime.Now.ToString(); } }public string MyMethod(){return DateTime.Now.ToString();}
}
调用测试方法统一如下：
BenchmarkRunner.Run<TestProperty>();
第一组：构造实例化对象和方法内实例化对象，调用属性差多少
[MemoryDiagnoser]
public class TestProperty
{private readonly MyClass _myClass;public TestProperty(){_myClass = new MyClass();}[Benchmark]public string PropertyA(){return _myClass.MyProperty1;}[Benchmark]public string PropertyAExt(){var myClass = new MyClass();return myClass.MyProperty1;}
}
结果：差别很大，因为毕竟有一个new的过程，需要开销，同时也能理解，提交初始尽量初始化，多次调用时就开销变少了。
第二组：比较用字段属性和无字段属性的差别
[MemoryDiagnoser]
public class TestProperty
{private readonly MyClass _myClass;public TestProperty(){_myClass = new MyClass();}[Benchmark]public string PropertyA(){return _myClass.MyProperty1;}[Benchmark]public string PropertyAExt(){var myClass = new MyClass();return myClass.MyProperty1;}[Benchmark]public string PropertyB(){return _myClass.MyProperty2;} [Benchmark]public string PropertyBExt(){var myClass = new MyClass();return myClass.MyProperty2;}
}
结果：这组结果显示，有字段的属性更快，因为当类实体化时，字段的值已经初始化完成，所以PropertyA要好于PropertyB，关于PropertyBExt，初始化字段+实例化对象，都占了300ns。
第三组：用反射访问属性与正常访问属性对比
[MemoryDiagnoser]
public class TestProperty
{private readonly MyClass _myClass;private readonly PropertyInfo _proinfo;public TestProperty(){_myClass = new MyClass();_proinfo = _myClass.GetType().GetProperty("MyProperty");}[Benchmark]public string PropertyA(){return _myClass.MyProperty1;}[Benchmark]public string PropertyAExt(){var myClass = new MyClass();return myClass.MyProperty1;}[Benchmark]public string PropertyB(){return _proinfo.GetValue(_myClass).ToString();}[Benchmark]public string PropertyBExt(){var myClass = new MyClass();var proinfo = myClass.GetType().GetProperty("MyProperty");return proinfo.GetValue(myClass).ToString();}
}
结果：反射调用肯定要比正常调用差一些，无可厚非，仅供参考
第四组：重点看一下代理的性能比较
[MemoryDiagnoser]
public class TestProperty
{private readonly MyClass _myClass;private readonly PropertyInfo _proinfo;private readonly Func<MyClass, string> _delegate;public TestProperty(){_myClass = new MyClass();_proinfo = _myClass.GetType().GetProperty("MyProperty1");_delegate = (Func<MyClass, string>)Delegate.CreateDelegate(typeof(Func<MyClass, string>), _proinfo.GetGetMethod(true)!);}[Benchmark]public string PropertyA(){return _myClass.MyProperty1;}[Benchmark]public string PropertyAExt(){var myClass = new MyClass();return myClass.MyProperty1;}[Benchmark]public string PropertyB(){return _proinfo.GetValue(_myClass).ToString();}[Benchmark]public string PropertyBExt(){var myClass = new MyClass();var proinfo = myClass.GetType().GetProperty("MyProperty1");return proinfo.GetValue(myClass).ToString();}[Benchmark]public string PropertyC(){var value = _delegate(_myClass);return value;}[Benchmark]public string PropertyCExt(){var myClass = new MyClass();var proinfo = myClass.GetType().GetProperty("MyProperty1");var dele = (Func<MyClass, string>)Delegate.CreateDelegate(typeof(Func<MyClass, string>), proinfo.GetGetMethod(true)!);return dele(_myClass);}
}
结果：PropertyC代理方式与PropertyA接近，看来在其他场景中可以参考使用。但PropertyCExt要开销的多的多，看来这是提前在实例化时做了工作，所以在代理调用时才开销变少。
