尝试使用 new Func来理解维基百科策略模式示例
我正在看这个， http://en.wikipedia.org/wiki/Strategy_pattern 和我理解策略模式的概念，但有人可以解释一下 C# 示例吗？
我真的不明白 Context 类中“策略”定义的方式和原因，为什么它是 Func 但随后只传递了两个参数，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);
}
}
I was looking at this, http://en.wikipedia.org/wiki/Strategy_pattern and I understand the concept of the strategy pattern, but could someone explain the C# example a bit.
I dont really get the how and why of the definition of 'Strategy' in the Context class, why is it Func<T, T, T> but then just two params are passed in eg 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);
}
}
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Func是以下形式的委托：因此，Func 有 2 个参数类型和 1 个返回类型。因此，当使用该函数时，您将输入
A
Func<T1,T2,TResult>is a delegate in the form of:so, the Func has 2 argument types, and 1 return type. Therefore when consuming the func, you'll type
Func是一个接受两个 int 参数并返回一个 int 的 func - Func 定义中的最后一个类型是返回类型。Func<int, int, int>is a func that take two int arguments and returns an int - the last type in a Func definition is the return type.Func是委托。委托是一种代表单个函数的类型。在 C# 中，您可以使用这样的函数，而不是声明特定的接口。如果您愿意，您可以使用如下所示的界面：A
Func<T, T1, T2>is a delegate. A delegate is a type which represents a single function. In C# you can use functions like this instead of declaring a specific interface. If you wanted, you could use an interface which would look something like this:Func是委托，并且 任何委托都可以被视为匿名接口。A
Func<T, T1, T2>is a delegate, and any delegate can be viewed as an anonymous interface.