C#委托(Delegate、Action、Func)体验

delegate

最基本的委托形式,必须要先定义委托

class DelegateDemo
{
    //定义委托
    public delegate void Run();
    public Run r;
    public DelegateDemo()
    {
        addDelegate(run1);
        addDelegate(run2);
        addDelegate(run3);
        addDelegate(run4);
        addDelegate(run4);
        r();
    }

    void addDelegate(Run fun)
    {
        if (r == null)
        {
            r = fun;
        }
        else
        {
            r += fun;
        }
    }

    public void run1()
    {
        Console.WriteLine("Delegate_1");
    }

    public void run2()
    {
        Console.WriteLine("Delegate_2");
    }

    public void run3()
    {
        Console.WriteLine("Delegate_3");
    }

    public void run4()
    {
        Console.WriteLine("Delegate_4");
    }
}

action

委托的泛型，具有N个参数可以指定，不能指定返回值

class ActionDemo
{
    public Action<string> act;
    public ActionDemo()
    {
        addDelegate(run1);
        addDelegate(run2);
        addDelegate(run3);
        addDelegate(run4);
        addDelegate(run4);
        act("a");
    }

    void addDelegate(Action<string> fun)
    {
        if (act == null)
        {
            act = fun;
        }
        else
        {
            act += fun;
        }
    }

    public void run1(string key)
    {
        Console.WriteLine("Action_1");
    }

    public void run2(string key)
    {
        Console.WriteLine("Action_2");
    }

    public void run3(string key)
    {
        Console.WriteLine("Action_3");
    }

    public void run4(string key)
    {
        Console.WriteLine("Action_4");
    }
}

Func

委托的泛型,具有N个参数并返回 TResult 参数指定的类型值的方法

class FuncDemo
{
    public Func<string, int> act;
    public FuncDemo()
    {
        addDelegate(run1);
        addDelegate(run2);
        addDelegate(run3);
        addDelegate(run4);
        addDelegate(run4);
        act("a");
    }

    void addDelegate(Func<string, int> fun)
    {
        if (act == null)
        {
            act = fun;
        }
        else
        {
            act += fun;
        }
    }

    public int run1(string key)
    {
        Console.WriteLine("Func_1");
        return 0;
    }

    public int run2(string key)
    {
        Console.WriteLine("Func_2");
        return 0;
    }

    public int run3(string key)
    {
        Console.WriteLine("Func_3");
        return 0;
    }

    public int run4(string key)
    {
        Console.WriteLine("Func_4");
        return 0;
    }
}