尝试使用新的Func <int,int,int>来理解维基百科策略模式示例

Question

我正在看这个,http://en.wikipedia.org/wiki/Strategy_pattern,我理解战略模式的概念,但有人可以解释一下C#的例子.

我真的不知道在Context类中定义"策略"的方式和原因,为什么它Func<T, T, T>只是两个参数传递给例如8,9？

static void Main(string[] args)
{

    var context = new Context<int>();

    // Delegate
    var concreteStrategy1 = new Func<int, int, int>(PerformLogicalBitwiseOr);

    // Anonymous Delegate
    var concreteStrategy2 = new Func<int, int, int>(
        delegate(int op1, int op2)
        {
            return op1 & op2;
        });

    // Lambda Expressions
    var concreteStrategy3 = new Func<int, int, int>((op1, op2) => op1 >> op2);
    var concreteStrategy4 = new Func<int, int, int>((op1, op2) => op1 << op2);

    context.Strategy = concreteStrategy1;
    var result1 = context.Execute(8, 9);

    context.Strategy = concreteStrategy2;
    var result2 = context.Execute(8, 9);

    context.Strategy = concreteStrategy3;
    var result3 = context.Execute(8, 1);

    context.Strategy = concreteStrategy4;
    var result4 = context.Execute(8, 1);

}

static int PerformLogicalBitwiseOr(int op1, int op2)
{
    return op1 | op2;
}

class Context<T>
{
    public Func<T, T, T> Strategy { get; set; }

    public T Execute(T operand1, T operand2)
    {
        return this.Strategy != null
            ? this.Strategy(operand1, operand2)
            : default(T);
    }
}

Answer 1

A Func<T1,T2,TResult>是以下形式的代表:

TResult function(T1 arg1, T2 arg2)

所以,Func有2个参数类型,1个返回类型.因此,在使用func时,您将键入

 (arg1, arg2) => return new TResult();