要在控件上创建新的事件处理程序,可以这样做

c.Click += new EventHandler(mainFormButton_Click);

或者这个

c.Click += mainFormButton_Click;

要删除事件处理程序,可以这样做

c.Click -= mainFormButton_Click;

但是如何从事件中删除所有事件处理程序呢?


当前回答

哇。我找到了这个解决方案,但没有一个像我想要的那样有效。但这个太好了:

EventHandlerList listaEventos;

private void btnDetach_Click(object sender, EventArgs e)
{
    listaEventos = DetachEvents(comboBox1);
}

private void btnAttach_Click(object sender, EventArgs e)
{
    AttachEvents(comboBox1, listaEventos);
}

public EventHandlerList DetachEvents(Component obj)
{
    object objNew = obj.GetType().GetConstructor(new Type[] { }).Invoke(new object[] { });
    PropertyInfo propEvents = obj.GetType().GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance);

    EventHandlerList eventHandlerList_obj = (EventHandlerList)propEvents.GetValue(obj, null);
    EventHandlerList eventHandlerList_objNew = (EventHandlerList)propEvents.GetValue(objNew, null);

    eventHandlerList_objNew.AddHandlers(eventHandlerList_obj);
    eventHandlerList_obj.Dispose();

    return eventHandlerList_objNew;
}

public void AttachEvents(Component obj, EventHandlerList eventos)
{
    PropertyInfo propEvents = obj.GetType().GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance);

    EventHandlerList eventHandlerList_obj = (EventHandlerList)propEvents.GetValue(obj, null);

    eventHandlerList_obj.AddHandlers(eventos);
}

其他回答

如果你真的要这么做……这需要深思熟虑和相当长的时间。事件处理程序在控件内的事件委托映射中进行管理。你需要

在控件实例中反射并获取此映射。 迭代每个事件,获取委托 每个委托可以依次是一系列链接的事件处理程序。调用obControl。RemoveHandler(事件处理程序)

简而言之,工作量很大。在理论上是可能的。我从没试过这样的东西。

看看是否可以对订阅-退订阶段有更好的控制/纪律。

你们对自己太苛刻了。很简单:

void OnFormClosing(object sender, FormClosingEventArgs e)
{
    foreach(Delegate d in FindClicked.GetInvocationList())
    {
        FindClicked -= (FindClickedHandler)d;
    }
}

从删除所有事件处理程序:

Directly no, in large part because you cannot simply set the event to null. Indirectly, you could make the actual event private and create a property around it that tracks all of the delegates being added/subtracted to it. Take the following: List<EventHandler> delegates = new List<EventHandler>(); private event EventHandler MyRealEvent; public event EventHandler MyEvent { add { MyRealEvent += value; delegates.Add(value); } remove { MyRealEvent -= value; delegates.Remove(value); } } public void RemoveAllEvents() { foreach(EventHandler eh in delegates) { MyRealEvent -= eh; } delegates.Clear(); }

删除不存在的事件处理程序不会造成任何损害。因此,如果您知道可能存在哪些处理程序,您可以简单地删除它们。我刚遇到过类似的情况。这在某些情况下可能会有帮助。

如:

// Add handlers...
if (something)
{
    c.Click += DoesSomething;
}
else
{
    c.Click += DoesSomethingElse;
}

// Remove handlers...
c.Click -= DoesSomething;
c.Click -= DoesSomethingElse;

哇。我找到了这个解决方案,但没有一个像我想要的那样有效。但这个太好了:

EventHandlerList listaEventos;

private void btnDetach_Click(object sender, EventArgs e)
{
    listaEventos = DetachEvents(comboBox1);
}

private void btnAttach_Click(object sender, EventArgs e)
{
    AttachEvents(comboBox1, listaEventos);
}

public EventHandlerList DetachEvents(Component obj)
{
    object objNew = obj.GetType().GetConstructor(new Type[] { }).Invoke(new object[] { });
    PropertyInfo propEvents = obj.GetType().GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance);

    EventHandlerList eventHandlerList_obj = (EventHandlerList)propEvents.GetValue(obj, null);
    EventHandlerList eventHandlerList_objNew = (EventHandlerList)propEvents.GetValue(objNew, null);

    eventHandlerList_objNew.AddHandlers(eventHandlerList_obj);
    eventHandlerList_obj.Dispose();

    return eventHandlerList_objNew;
}

public void AttachEvents(Component obj, EventHandlerList eventos)
{
    PropertyInfo propEvents = obj.GetType().GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance);

    EventHandlerList eventHandlerList_obj = (EventHandlerList)propEvents.GetValue(obj, null);

    eventHandlerList_obj.AddHandlers(eventos);
}