Action<T>泛型委托

描述:

封装一个方法,该方法只采用一个参数并且不返回值.

语法:

public delegate void Action<T>(T arg);

T:

参数类型:此委托封装的方法的参数类型

arg:

参数:此委托封装的方法的参数

备注:

通过此委托,可以将方法当做参数进行传递.

其他形式:

public delegate void Action<T1, T2>(T1 arg1, T2 arg2);
public delegate void Action<T1, T2, T3>(T1 arg1, T2 arg2, T3 arg3);
public delegate void Action<T1, T2, T3, T4>(T1 arg1, T2 arg2, T3 arg3, T4 arg4);

例子:

protected void Page_Load(object sender, EventArgs e)
{
    List<int> list = new List<int>();
    list.AddRange(new int[] { 7, 6, 10, 1, 2, 3, 4, 5, 8 });

    Action<int> action = new Action<int>(AddFive);
    list.ForEach(action);

    //效果同
    //      Action<int> action = new Action<int>(AddFive);
    //      list.ForEach(action);
    //list.ForEach(x => Response.Write((x + 5).ToString() + "<br/>"));

    //效果同
    //      Action<int> action = new Action<int>(AddFive);
    //      list.ForEach(action);
    //list.ForEach(delegate(int i)
    //{
    //    HttpContext.Current.Response.Write((i + 5).ToString() + "<br/>");
    //});
}

public static void AddFive(int i)
{
    HttpContext.Current.Response.Write((i + 5).ToString() + "<br/>");
}

结果:

12
11
15
6
7
8
9
10
13