我在 C# 中遇到了一些意外行为。我基本上是在尝试将一个操作分配给另一个操作的引用,以便我可以稍后订阅/取消订阅引用操作的方法。我不想知道实现引用操作的类。
问题是,应该指向我想听的 Action 的 Action 似乎并没有真正指向它。我认为它会在引发引用操作时引发,但显然情况并非如此。
我可能对委托(delegate)有一些误解。有人可以告诉我我做错了什么吗?是否有针对我要实现的目标的解决方案?
感谢任何回复!
public class WaitForActionProcess : IProcess
{
public Action Finished { get; set; }
Action actionHandler;
public WaitForActionProcess(ref Action action)
{
actionHandler = action;
}
public void Play()
{
actionHandler += RaiseFinished;
}
public void RaiseFinished()
{
actionHandler -= RaiseFinished;
if(Finished != null)
{
Finished();
}
}
}
使用示例:
public class ReturnToMainMenuFrame : TutorialEventFrame
{
[SerializeField]
TutorialDialogueData dialogueData;
[SerializeField]
PointingArrowData arrowData;
[SerializeField]
TutorialDialogue tutorialDialogue;
[SerializeField]
PointingArrow arrow;
[SerializeField]
MainView mainView;
public override void StartFrame()
{
frameProcesses.Add(new ShowPointToUIProcess(arrow, arrowData));
frameProcesses.Add(new ShowDialogueProcess(tutorialDialogue, dialogueData));
frameProcesses.Add(new WaitForActionProcess(ref mainView.OnViewShown));
frameProcesses.Add(new HideDialogueProcess(tutorialDialogue, this));
frameProcesses.Add(new HidePointToUIProcess(arrow,this));
base.StartFrame();
}
}
框架基础实现:
public class TutorialEventFrame : MonoBehaviour {
public delegate void OnFrameEnded();
public event OnFrameEnded FrameEnded;
public List<IProcess> frameProcesses = new List<IProcess>();
public bool debugMode = false;
public virtual void StartFrame()
{
StartProcess(0);
}
void StartProcess(int processIndex)
{
if (processIndex < frameProcesses.Count)
{
int nextProcessIndex = processIndex + 1;
frameProcesses[processIndex].Finished += () => StartProcess(nextProcessIndex);
}
else
{
EndFrame();
return;
}
if (debugMode)
{
Debug.Log("Starting process: " + frameProcesses[processIndex] + " of processes: " + (processIndex + 1) + "/" + (frameProcesses.Count - 1) + " on frame: " + name);
}
frameProcesses[processIndex].Play();
}
public virtual void EndFrame() {
foreach (var process in frameProcesses)
{
process.Finished = null;
}
if (debugMode)
{
Debug.Log("frame: " + name + " finished");
}
frameProcesses.Clear();
if (FrameEnded != null) {
FrameEnded();
}
}
}
最佳答案
假设 OnViewShown 是一个事件,并且你想在调用 Play 时开始监听这个事件,然后在事件触发时调用 Finished,下面将允许你这样做:
public class WaitForActionProcess : IProcess
{
public Action Finished { get; set; }
Action<Action> Subscribe { get; }
Action<Action> Unsubscribe { get; }
public WaitForActionProcess(Action<Action> subscribe, Action<Action> unsubscribe)
{
Subscribe = subscribe;
Unsubscribe = unsubscribe;
}
public void Play()
{
Subscribe(RaiseFinished);
}
public void RaiseFinished()
{
Unsubscribe(RaiseFinished);
Finished?.Invoke();
}
}
调用方法:
var wfap = new WaitForActionProcess(
h => mainView.OnViewShown += h,
h => mainView.OnViewShown -= h);
请注意,您希望 100% 确定 OnViewShown 将在播放后触发,否则将永远不会调用 Finished,并且您还会遇到内存泄漏,因为您永远不会取消订阅该事件。
虽然它可能在 Unity 中不可用,但请查找 System.Reactive,它使此类事情形式化并使事件处理更易于管理。
关于c# - 如何创建指向另一个 Action C# 的 Action?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50751996/