另一个类中的动作委托引用？
我正在寻找一种方法来允许另一个类通过调用该类的方法向我的 Action 委托添加方法，而不是在第一个类上调用 Action。
这就是我需要的：
class Program
{
static void Main(string[] args)
{
Action Execute = delegate { };
ProgramTest prog = new ProgramTest(ref Execute);
prog.AddMethod();
Execute();
}
}
class ProgramTest
{
public Action execute;
public ProgramTest(ref Action action)
{
execute = action;
}
public void AddMethod()
{
execute += Print;
}
public void Print()
{
Console.WriteLine("test");
Console.ReadLine();
}
}
但是，当我调用 Execute() 时，什么也没有发生。
我怎样才能让它工作？
潇潇雨雨浏览 67回答 4
4回答
-
慕容3067478
另一种选择是将（不可变的）委托放在可变容器中。public class ActionContainer{ public Action Action { get; set; } = () => { };}class Program{ static void Main(string[] args) { ActionContainer execute = new ActionContainer(); ProgramTest prog = new ProgramTest(execute); prog.AddMethod(); execute.Action(); }}class ProgramTest{ public ActionContainer execute; public ProgramTest(ActionContainer action) { execute = action; } public void AddMethod() { execute.Action += Print; } public void Print() { Console.WriteLine("test"); Console.ReadLine(); }} -
精慕HU
你想要的是这样的：class Program{ static void Main(string[] args) { Action Execute = delegate { }; ProgramTest prog = new ProgramTest(h => Execute += h); prog.AddMethod(); Execute(); }}class ProgramTest{ public Action<Action> execute; public ProgramTest(Action<Action> action) { execute = action; } public void AddMethod() { execute(Print); } public void Print() { Console.WriteLine("test"); Console.ReadLine(); }}打印test到控制台。这是这个模式的一个稍微好一点的版本：class Program{ static void Main(string[] args) { Action Execute = delegate { }; ProgramTest prog = new ProgramTest(h => Execute += h, h => Execute -= h); var subscription = prog.AddMethod(); Execute(); subscription.Dispose(); }}class ProgramTest{ public Action<Action> _attach; public Action<Action> _detach; public ProgramTest(Action<Action> attach, Action<Action> detach) { _attach = attach; _detach = detach; } public IDisposable AddMethod() { _attach(Print); return Disposable.Create(() => _detach(Print)); } public void Print() { Console.WriteLine("test"); Console.ReadLine(); }}public sealed class Disposable : IDisposable{ public static IDisposable Create(Action action) => new Disposable(action); private readonly Action _action; private int _disposed; private Disposable(Action action) { _action = action; } public void Dispose() { if (Interlocked.Exchange(ref _disposed, 1) == 0) { _action(); } }}我什至会更进一步并定义一个MetaAction- 您可以随意传递它并向其添加方法。class Program{ static void Main(string[] args) { Action Execute = delegate { }; MetaAction meta = MetaAction.Create(h => Execute += h, h => Execute -= h); var prog = new ProgramTest(meta); var subscription = prog.AddMethod(); Execute(); subscription.Dispose(); }}public class MetaAction{ public static MetaAction Create(Action<Action> attach, Action<Action> detach) => new MetaAction(attach, detach); public Action<Action> _attach; public Action<Action> _detach; private MetaAction(Action<Action> attach, Action<Action> detach) { _attach = attach; _detach = detach; } public IDisposable Subscribe(Action action) { _attach(action); return Disposable.Create(() => _detach(action)); }}public class ProgramTest{ public MetaAction _meta; public ProgramTest(MetaAction meta) { _meta = meta; } public IDisposable AddMethod() { return _meta.Subscribe(Print); } public void Print() { Console.WriteLine("test"); Console.ReadLine(); }}public sealed class Disposable : IDisposable{ public static IDisposable Create(Action action) => new Disposable(action); private readonly Action _action; private int _disposed; private Disposable(Action action) { _action = action; } public void Dispose() { if (Interlocked.Exchange(ref _disposed, 1) == 0) { _action(); } }} -
慕标5832272
您可以通过调用 prog.Execute 而不是 Execute 来使其工作，就像下面的代码一样。class Program{ static void Main(string[] args) { Action Execute = delegate { }; ProgramTest prog = new ProgramTest(ref Execute); prog.AddMethod(); prog.execute(); }}或者您需要将 Print 方法分配给 main 方法执行委托，如下所示class Program{ static void Main(string[] args) { Action Execute = delegate { }; ProgramTest prog = new ProgramTest(ref Execute); Execute += prog.Print; prog.AddMethod(); Execute(); }} -
qq_花开花谢_0
您Program可能会公开一个事件，您的其他类可能会向该事件注册另一个处理程序：class Program{ public static event Action MyEvent; static void Main(string[] args) { ProgramTest prog = new ProgramTest(); prog.AddMethod(); // raise the event and invoke the registered handlers MyEvent?.Invoke(); }}class ProgramTest{ private Action handler; public ProgramTest() { handler = Print; } public void AddMethod() { Program.MyEvent += handler; // regsiter the execute-delegate to the event // or directly: Program.MyEvent += Print; } public void Print() { Console.WriteLine("test"); Console.ReadLine(); }}
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C#