//反射
public static void ReflectionUse(AnObject o, object parameter)
{
var parameters = new[] { parameter };
var sw = new Stopwatch();
sw.Start();
var methodInfo = typeof(AnObject).GetMethod("Call");
for (int i = 0; i < times; i++)
{
methodInfo.Invoke(o, parameters);
}
sw.Stop();
Console.WriteLine("反射调用方法: " + sw.ElapsedMilliseconds);
sw.Restart();
var properties = typeof(AnObject).GetProperty("a");
for (int i = 0; i < times; i++)
{
var a = properties.GetValue(o, null);
}
sw.Stop();
Console.WriteLine("反射获取属性: " + sw.ElapsedMilliseconds);
}
//使用表达式
public static void ExpressionUse(AnObject o, object parameter)
{
var sw = new Stopwatch();
sw.Start();
var exp = GetAction();
for (var i = 0; i < times; i++)
{
exp(o, parameter);
}
sw.Stop();
Console.WriteLine("表达式调用方法: " + sw.ElapsedMilliseconds);
sw.Start();
var exp2 = GetFunc(o);
for (var i = 0; i < times; i++)
{
var a = exp2(o);
}
sw.Stop();
Console.WriteLine("表达式获得属性: " + sw.ElapsedMilliseconds);
}
//构造函数传入欲获得字段的propertyInfo
public GetterWrapper(AnObject o, PropertyInfo propertyInfo)
{
var m = propertyInfo.GetGetMethod(true);
//构造一个强类型的委托
_getter = (Func <TTarget>)Delegate.CreateDelegate(typeof(Func <TTarget>), o, m);
}
static void Main(string[] args)
{
var o = new AnObject(1);
//强迫编译器JIT编译，生成方法的本地代码
//如果没有这步，后面方法的直接调用将会加入JIT编译的时间（尽管只有一点点）
//使得结果不准确
o.Call(null);
DirectUse(o, new object());
ReflectionUse(o, new object());
DelegateUse(o, new object());
GenericDelegateUse();
ExpressionUse(o, new object());
Console.ReadKey();
}
//直接调用
public static void DirectUse(AnObject o, object parameter)
{
var sw = new Stopwatch();
sw.Start();
for (int i = 0; i < times; i++)
{
o.Call(parameter);
}
sw.Stop();
Console.WriteLine("直接调用方法: " + sw.ElapsedMilliseconds);
sw.Restart();
for (int i = 0; i < times; i++)
{
var a = o.a;
}
sw.Stop();
Console.WriteLine("直接获取属性: " + sw.ElapsedMilliseconds);
}
public static void GenericDelegateUse()
{
var sw = new Stopwatch();
sw.Start();
var o = new AnObject(999);
var propertyInfo = typeof(AnObject).GetProperty("a");
//试图获得int类型的值
var genericDel = new GetterWrapper <int>(o, propertyInfo);
object a = 0;
for (var i = 0; i < times; i++)
{
a = genericDel.GetValue();
}
sw.Stop();
Console.WriteLine("属性的值：" + a); //999
Console.WriteLine("通用泛型委托获取属性: " + sw.ElapsedMilliseconds);
sw.Restart();
o.b = "test";
propertyInfo = typeof(AnObject).GetProperty("b");
//试图获得string类型的值
var genericDel2 = new GetterWrapper <string>(o, propertyInfo);
string b = "";
for (var i = 0; i < times; i++)
{
b = genericDel2.GetValue();
}
sw.Stop();
Console.WriteLine("属性的值：" + b); //test
Console.WriteLine("通用泛型委托获取属性: " + sw.ElapsedMilliseconds);
}
//委托调用
public static void DelegateUse(AnObject o, object parameter)
{
var parameters = new[] { parameter };
var sw = new Stopwatch();
sw.Start();
var methodInfo = typeof(AnObject).GetMethod("Call");
//通过类型对象和方法名建立强类型委托
var del = (CallBack)Delegate.CreateDelegate(typeof(CallBack), o, methodInfo);
for (int i = 0; i < times; i++)
{
//只能传入和输入方法相同类型和个数的输入，否则会导致无法通过编译
del.Invoke(o);
}
sw.Stop();
Console.WriteLine("委托调用方法: " + sw.ElapsedMilliseconds);
sw.Restart();
//获得a的getter的方法信息，getter的方法签名为无输入参数，有一个int的输出
methodInfo = typeof(AnObject).GetMethod("get_a");
var del2 = (ReadProperty)Delegate.CreateDelegate(typeof(ReadProperty), o, methodInfo);
//使用委托来调用getter获取属性
for (int i = 0; i < times; i++)
{
var a = del2();
}
sw.Stop();
Console.WriteLine("委托获取属性: " + sw.ElapsedMilliseconds);
}
